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My latest 650b low trail fredmobile for the peanut gallery
You may recall the knowledge dropping (and/or shit stirring) that I did in SignatureJustin's threads a few months back when he was looking for information on this sort of bike: http://www.velocipedesalon.com/forum...ead-30742.html | http://www.velocipedesalon.com/forum...ere-30790.html | http://www.velocipedesalon.com/forum...ack-31233.html — or the thread about that 650b Firefly — or my 6 post info bomb on wtf the deal is with porteur racks. If you can get past the butthurt those threads make for great background on what makes this more than a homercar.
Well I recently did the initial build on my latest one and have put 500 miles on it: New Elephant - a set on Flickr
http://farm4.staticflickr.com/3799/8...0b5bb174_b.jpg
Frame and fork built by Glen Copus of Elephant Bikes, see the BikeCAD Model for dimensions.
Versus my Rawland rSogn the chainstays and front-center are 1cm shorter each, the BB is 5mm lower, and the seat tube angle is nearly a degree slacker.
I designed around disc brakes so I could use cheap 650b carbon rims that are 20x stiffer and stronger than the light alloy ones I was using at the same weight (I 'm on my third rear rim on my Rawland!). The extra 4mm of inside width vs. a normal 23mm rim doesn't make the tires any wider, but it does make them significantly rounder which took a bit of getting used to.
The Extra Léger Hetres are set up tubeless, and the low rolling resistance of that combo is definitely noticeable, but I find myself inflating them to 30-35psi instead of 25-30 because of the lack of compression damping in the casing. The sidewalls even wrinkle visibly under load! I find normal Hetres at 20psi to still be perfectly rideable, but these sag a lot when that low and squeal obscenely just turning the bars on asphalt.
http://farm8.staticflickr.com/7322/8...d08117be_z.jpg http://farm6.staticflickr.com/5444/8...d9fbc02d_z.jpg
http://farm4.staticflickr.com/3753/8...cdbcb9dc_z.jpg http://farm4.staticflickr.com/3791/8...590e3a03_z.jpg
The bike is 23.3lbs as shown without fenders or bottlecages: frame is 4lbs even, fork is 2.2lbs, and the rack is 1.2lbs. I could shave at least a third of a pound off the rack by making it in 5/16" x 0.028" instead of 3/8" x 0.035", and might do that next time, I just didn't want to change to many variables in the design at once.
The TT & DT are single oversize OX Platinum in 7/4/7 with the longest center butts, the seattube is 28.5 6/4/5 S3, the seatstays are also S3 in .5mm 16/11 taper, and the chainstays are from the Dedacciai 29er tubeset. The fork uses a Nova crown with matching oversize 29/21 blades and a superlight steerer (normal steel 9/8" steerers are thick enough to thread for some fucking reason).
By the numbers the front end should be marginally stiffer than my 9/6/9 standard-diameter bikes (like Columbus SL). I was pleasantly surprised that it's definitely a bit more flexible under pedaling, but also doesn't get bounced off its line as much plowing through a rock garden. Perhaps the superlight seat tube has something to do with that, but it's hard to tell. See the porteur rack thread for details, but the main charm of this sort of geometry is that you can build the frame to be super responsive/sprightly without affecting the load-carrying ability.
Here it is dirty on my way home from an overnight bike camping trip on the North Fork Snoqualmie:
http://farm3.staticflickr.com/2838/8...4e2a5a9f_b.jpg
Obviously it still needs to be painted, that'll get done in a few couple months with a rather ridiculous design, the vintage splash tape should serve as a clue.
I still need to add some bosses and wire anchor points to the front rack, make a custom mini rear rack for it to hold a stuffsack when camping and serve as a taillight mount, make some weigle-style mounting hardware for the Honjo fenders I have for it, do a custom wiring harness with lapel-mic cable, and machine accessory clamps for the paired triple seat tube bosses to hold a pump and/or folding saw.
When the rain starts letting up again I'll put 2.3" knobbies on it and take it out for some real mountain biking.
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Re: My latest 650b low trail fredmobile for the peanut gallery
Cool.
I believe I was promised peanuts?
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Re: My latest 650b low trail fredmobile for the peanut gallery
My mind has been officially blown.
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Re: My latest 650b low trail fredmobile for the peanut gallery
What's the advantage of carrying all the weight over the front wheel instead of behind the rider? Curious because I don't know. Not an expert on touring/utility bikes.
BTW, that thing rocks. What's the tail light?
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Re: My latest 650b low trail fredmobile for the peanut gallery
Quote:
Originally Posted by
Saab2000
What's the advantage of carrying all the weight over the front wheel instead of behind the rider? Curious because I don't know. Not an expert on touring/utility bikes.
basically you can make the frame as if it didn't have to carry a load at all, no extra stiffness to resist the torque of rear racks, the tail wagging the dog, or any of that jazz
it can respond to your pedaling like a race bike instead of a turdly surly
with the proper fork geometry, you don't feel the weight even riding out of the saddle (unlike a saddlebag) and the bike still corners awesome
it's also *more* aerodynamic than a pair of rear panniers — think about how airfoils work, it makes the bag a fairing instead of a pair of air-brakes
there's a bunch more info in http://www.velocipedesalon.com/forum...ack-31233.html and http://www.velocipedesalon.com/forum...why-30681.html
Quote:
Originally Posted by
Saab2000
What's the tail light?
Philips - SafeRide LightRing Dynamo SRRDLGBLX1 - Rear lights - LED bicycle lights - Lighting
It fell off later that week because I left the QR functionality intact but then couldn't get the tiny retainer screw in with the fender in the way.
http://farm6.staticflickr.com/5337/8...40bcdd2e_b.jpg
I mounted the battery version of the same light for a 400k Brevet
I'll probably end up mounting a rack style light like the B&M Toplight Linetec once I make the custom mini rear rack to put it on.
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Re: My latest 650b low trail fredmobile for the peanut gallery
Thank you, it was getting to the point where I had confused 650b with having the bars higher than the saddle. Who would've known it was a wheel size?
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Re: My latest 650b low trail fredmobile for the peanut gallery
Sweet, like the quadra-plated dual fork setup.
Is this thing:
a) more racy than the Rawland
b) about the same
c) can't tell the tires are chubbed-out.
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Re: My latest 650b low trail fredmobile for the peanut gallery
the tires are somewhat chubbed out
but there's a distinct difference between rolling resistance and how fast the frame wants you to pedal it
and the frame is absolutely racier than my Rawland in terms of pedaling response (what Jan calls 'planing')
it is kinda hard to isolate what difference the carbon rims make not having ridden it with other wheels
and it'd be interesting to build another otherwise-identical fork with the tandem chainstays for blades to see what difference that would make (other than the extra half pound)
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Re: My latest 650b low trail fredmobile for the peanut gallery
Really like it. All purpose, no bullshit.
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Re: My latest 650b low trail fredmobile for the peanut gallery
Quote:
Originally Posted by
Saab2000
What's the advantage of carrying all the weight over the front wheel instead of behind the rider? Curious because I don't know. Not an expert on touring/utility bikes.
BTW, that thing rocks. What's the tail light?
Adding to Fred's comments, I find it Porteur much more practical for city commuting and errand runs. One big bag right at your hands is easier to get and bring in to the many different places I may stop at on a ride. Almost the convenience of a messenger bag, none of the discomfort.
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Will you share the front end geometry?
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Re: My latest 650b low trail fredmobile for the peanut gallery
Quote:
Originally Posted by
thollandpe
Will you share the front end geometry?
It's all in BikeCAD — but that's probably a bit obtuse to poke around in if you haven't used it before
HTA is 73° with 65mm of fork offset, that means 35mm of trail on Hetres.
My Rawland was supposed to be 73°/63mm but the actual HTA was closer to 73.5° (among other things that were off)
I intentionally had the fork made 10-15mm taller than necessary to make the rack design simpler
As a side-effect that also makes it possible to convert it to traditional 72°/47mm cyclocross geometry with an off-the-shelf carbon disk fork.
Other notable measurements: the chainstays are 435mm, front-center is 633mm, and the STA is around 71.5° (I eat setback for breakfast)
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Re: My latest 650b low trail fredmobile for the peanut gallery
glen is cool
lack of panniers is cool
your bike is cool (cable routing ftw)
we should be friends
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Re: My latest 650b low trail fredmobile for the peanut gallery
I don't know shit about lowtrail/650b-nerdyness but this tread is fucking awesome.
Sounds like you're STOKED on your new rig and know what you wanted geometry wise.
Couldn't ask for more!
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Re: My latest 650b low trail fredmobile for the peanut gallery
It looks like you're having some fun on that machine. One question: why is your FD cable housing run along the top location instead of on the bottom where it would free up your other two housing runs? The mechanic in me might choose that option, which seems available to you.
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Re: My latest 650b low trail fredmobile for the peanut gallery
Quote:
Originally Posted by
Matthew J
Really like it. All purpose, no bullshit.
Let's not get carried away . . .
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Re: My latest 650b low trail fredmobile for the peanut gallery
Quote:
Originally Posted by
Brian Smith
why is your FD cable housing run along the top location instead of on the bottom where it would free up your other two housing runs? The mechanic in me might choose that option, which seems available to you.
It really does work best this way for all three housing runs, I tried out every permutation.
Using the upper stops for the rear loops makes them stick up significantly more, and they don't arc around the seat tube as nicely without the FD loop lying underneath them.
The FD loop also gets a better radius using the upper loop, and moving its adjuster stop down the seat tube wouldn't help that much. Moving the TT stops forward would help relax it more but also put them where my knee might hit them.
The one thing that's suboptimal about the arrangement is the need to have assembled the stops out of individual ones. AFAICT nobody's made an integrated triple-stop for a 28.6 tube in a long time, and machining a pair would have been really annoying. If anyone has a stockpile of such bosses or knows where to get them, I'm all ears.
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Re: My latest 650b low trail fredmobile for the peanut gallery
No matter what's bolted to them, it's not a rando bike without a 110bcd Ritchey Logic square taper crank, ya heard!
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Re: My latest 650b low trail fredmobile for the peanut gallery
beauty of the bicycle.
you can do a lot of different things.
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Re: My latest 650b low trail fredmobile for the peanut gallery
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Re: My latest 650b low trail fredmobile for the peanut gallery
glad it works for you.
why did you put red tape on the top tube cable stops? were you snagging shorts or your skin? i've never had good experiences with cable stops at 3 or 9 o'clock.
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Re: My latest 650b low trail fredmobile for the peanut gallery
Quote:
Originally Posted by
nate2351
No matter what's bolted to them, it's not a rando bike without a 110bcd Ritchey Logic square taper crank, ya heard!
Is it meant to be a Rando? Looks as though it would do quite well as a road / off road utility machine.
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Re: My latest 650b low trail fredmobile for the peanut gallery
Quote:
Originally Posted by
blasdelf
The Extra Léger Hetres are set up tubeless, and the low rolling resistance of that combo is definitely noticeable, but I find myself inflating them to 30-35psi instead of 25-30 because of the lack of compression damping in the casing. The sidewalls even wrinkle visibly under load! I find normal Hetres at 20psi to still be perfectly rideable, but these sag a lot when that low and squeal obscenely just turning the bars on asphalt.
I am still in disbelief that Extra Leger Hetres can hold air tubeless. The Extra Leger sidewall is paper thin. Any issues so far?
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Re: My latest 650b low trail fredmobile for the peanut gallery
On paper, I'm not a fan of low-trail (I made mine to have mega trail, ultra slack front end with loads of front-center). But I've never ridden a low-trail bike (that I know of), so I'm judging without first-hand experience. I like the custom idea though, and the fact you're stoked about it. Bike tires on a roadie -- big grins from me.
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Re: My latest 650b low trail fredmobile for the peanut gallery
Quote:
Originally Posted by
David Tollefson
On paper, I'm not a fan of low-trail (I made mine to have mega trail, ultra slack front end with loads of front-center). But I've never ridden a low-trail bike (that I know of), so I'm judging without first-hand experience. I like the custom idea though, and the fact you're stoked about it. Bike tires on a roadie -- big grins from me.
It makes a big difference when you are carrying weight up front.
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Re: My latest 650b low trail fredmobile for the peanut gallery
Elegant rack/crown interface - any dif in handling raising it vs. the R?
32 3x f/r ...what spokes?
Superlight steerer - that's a proprietary name right... you mentioned tandem cs for possible future fork blades - what's the compliance in the front like currently/must a load be carried to dampen things out.
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Re: My latest 650b low trail fredmobile for the peanut gallery
Cool bike. I love everything about it. Tell me more about the top pull Sram FD? any comments on that geo when not riding with a load on the front?
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Re: My latest 650b low trail fredmobile for the peanut gallery
Quote:
Originally Posted by
nate2351
No matter what's bolted to them, it's not a rando bike without a 110bcd Ritchey Logic square taper crank, ya heard!
I've got three pairs in 180mm
Though the true holy grail for that type of rando dork is the 94bcd version, I've got a few friends with hoards of them that get used as 46/30 or 42/29 doubles
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Re: My latest 650b low trail fredmobile for the peanut gallery
Quote:
Originally Posted by
timto
Tell me more about the top pull Sram FD?
From the pictures it looks like he bolted another piece in place of the existing cable-pinch bolt to reverse the cable pull direction. Am I right blasdelf? That's very clever.
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Re: My latest 650b low trail fredmobile for the peanut gallery
Quote:
Originally Posted by
roseyscot
why did you put red tape on the top tube cable stops? were you snagging shorts or your skin? i've never had good experiences with cable stops at 3 or 9 o'clock.
It caught on some loose thin pants a couple times an hour, I'll hit it with a deburring tool when I get back into the shop and it should be fine.
I routed the cables that way so that the top tube would be maximally sittable on, and also be good for shouldering from the NDS. I didn't want anything internal, and having nothing on the DT makes it a better handle (pretty much the way to portage a porteur).
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Re: My latest 650b low trail fredmobile for the peanut gallery
Quote:
Originally Posted by
zandrrr
From the pictures it looks like he bolted another piece in place of the existing cable-pinch bolt to reverse the cable pull direction. Am I right blasdelf? That's very clever.
Indeed
It's a Speen Umlenker, he's done the scut work of figuring out the geometries of all the major front derailleurs, making it much easier to buy than build.
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Re: My latest 650b low trail fredmobile for the peanut gallery
Quote:
Originally Posted by
sparky33
I am still in disbelief that Extra Leger Hetres can hold air tubeless. The Extra Leger sidewall is paper thin. Any issues so far?
They swallowed up about an oz of sealant, and they got pinholes around the edges of the tread, but that's all quite normal for tubeless with nice tires.
The annoying thing about them is having to pump them up more to feel right — like a suspension fork that has great small-bump response but really because the compression damper is detuned, so you need a bigger spring to avoid wallowing in the travel.
I ride normal Hetres with tubes at 20-30psi, the EL Hetres tubeless want around 35psi. If I let them down around 20 they wrinkle visibly when I get on, and squeal on the asphalt just riding out of my driveway.
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Re: My latest 650b low trail fredmobile for the peanut gallery
Quote:
Originally Posted by
jitahs
Elegant rack/crown interface - any dif in handling raising it vs. the R?
Once it's above the wheel, the height of the load isn't really noticeable until you get to extremes: like bundles of firewood that extend up over the bars, or piling a dozen tallboys on top of the stuff you already had in the bag.
Height does matter more than fore/aft placement, but centering the load left/right is the real sticking point. Part of that is that you really want to balance density, not just weight / center-of-gravity.
As such I didn't really design around it, but I just checked and the platform on the latest rack is actually almost an inch lower than the one on my Rawland:
http://i.imgur.com/dxxDwh.jpg
On the Rawland I had one fender boss on the rack, positioned directly over the axle, and placed everything to keep the tire clearance the same there as at the boss under the fork crown.
On the new bike there's intentionally no direct fender boss under the crown, and once I put the Honjos on there will be two fender bosses on the rack facing the axle with it centered between them:
http://i.imgur.com/qR313JDh.png
This ends up conserving the same tire clearance, because the mounts are along a chord rather than tangent right at the peak.
Quote:
Originally Posted by
jitahs
32 3x f/r ...what spokes?
DT SuperComps, which also make aluminum nipples viable because the 1.8mm threads give them more meat
Quote:
Originally Posted by
jitahs
Superlight steerer - that's a proprietary name right...
Normal steel steerers have been 2.3mm thick at the bottom and 1.6mm thick at the upper end since time immemorial, a 1" OD tube ends up with a 7/8" ID at the top and it happens to make them thick enough to thread and slot for a keyway. Everything's been threadless for 15 years, but for some fucking reason almost nobody bothers to use thinner steerers even on modern 1 1/8" stuff (some at least started making them 2.1mm at the thick end).
True Temper used to make a thin 1" threadless steerer that was the lightest setup around, but that's been out of production for a decade. Thankfully they still make 1 1/8" 1.65/1.14mm steerers in both 4130 and OX Platinum. Sometimes you have to bend the flanges on a star-nut to get a good fit on the larger ID, but there's really no downside or even a cost difference.
If you wanna calculate the weight difference or dent resistance, here's a spreadsheet for your edification: https://docs.google.com/spreadsheet/...vMWt1ckE#gid=0
Quote:
Originally Posted by
jitahs
you mentioned tandem cs for possible future fork blades - what's the compliance in the front like currently/must a load be carried to dampen things out.
The fork is pretty beef, the blades are a little bigger than normal oversized, and less ovalized too. Despite that it does have some flexibility in it at least laterally, it'll probably get put in the fork deflection tester that BQ built at some point to really find out.
Unless it's truly extreme like one built with undersized super-tapered Imperial Oval blades or an old Time 1" carbon fork, any compliance in the fork is *very* hard to perceive over the tires.
You can get to the other extreme with an oversize straight-gauge segmented fork that has all of its offset at the crown, or by building a beefy porteur rack that goes all the way to the dropouts, or with a truss spaceframe like Jeff Jones does, or any of the superbeef insanity that Chalo needs to not break shit JRA.
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Re: My latest 650b low trail fredmobile for the peanut gallery
Quote:
Originally Posted by
timto
any comments on that geo when not riding with a load on the front?
it's not as understable / nervous / supermanueverable as my previous lowtrailbro bikes when ridden without a load
the steering geometry isn't really different from the previous incarnations
I suspect the rounder tire profile is playing a large part in the difference, I could pick that out of the haystack immediately when I rode it the first time
the fit is better too, and I'm talking about balance not goddamn contact points — e-richie's "putting the wheels in the right place"
also the frame alignment is probably better, my old Kogswell was quite off especially towards the end of its life
if you know the handling difference between a standard cyclocross bike and an italian-style road bike, this one is about that much more manueverable than the road bike
with 5-35lbs added, it's more neutral like the road bike, but still different in character (I'm too habituated to it to describe better as I've been riding these for 6 years)
the weight of the load also pretty much disappears while you're riding, obviously you still expend energy to get the load up hill, but it's like waterbottles not panniers
and the absolute opposite of having 10 pounds in a saddlebag, which makes the bike feel like it weighs 200lbs the second you get out of the saddle
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Re: My latest 650b low trail fredmobile for the peanut gallery
Also speechless that these tires work tubeless. ELs are on backorder at Compass and I'd love to try them tubeless. Think it was worth the trouble? Sure seems like a lot of sealant.
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Re: My latest 650b low trail fredmobile for the peanut gallery
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Originally Posted by
summilux
Sure seems like a lot of sealant.
The 124g 650b tubes I use are exactly the same weight as 4oz of Stan's sealant. I'd guess that each tire had had maybe 3oz of sealant put into it so far, and at least a third of that has coagulated into the sidewalls (with most of the liquid it was suspended in evaporating). The weight of the valve is trivial, under 10g.
I'm far from the only one using these tubeless, I ran into a few others on an SIR brevet, and I know Peter Weigle has done a couple sets (including shaved tubeless!).
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Re: My latest 650b low trail fredmobile for the peanut gallery
Quote:
This ends up conserving the same tire clearance, because the mounts are along a chord rather than tangent right at the peak.
Apparently running the fender up btwn the mounts doesn't interfere with the bag.
Ok I get it: the carried weight is born by the fork/axle/wheel, not by the steerer at all.
Quote:
Unless it's truly extreme like one built with undersized super-tapered Imperial Oval blades or an old Time 1" carbon fork, any compliance in the fork is *very* hard to perceive over the tires.
True with the GBs at those volumes on those rims.
Thinking about the feasibility of converting an italo-roadie, griffin-style; Irina Shayk in the back, meat head in the front. Needs more study.
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Re: My latest 650b low trail fredmobile for the peanut gallery
Quote:
Originally Posted by
jitahs
; Irina Shayk in the back, meat head in the front.
I think I saw what you're looking for at the White Horse last friday.
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Re: My latest 650b low trail fredmobile for the peanut gallery
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Originally Posted by
spopepro
I think I saw what you're looking for at the White Horse last friday.
Yea anything close to the Tendernob (sic) is suspect. Beware what's under the boot.
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Re: My latest 650b low trail fredmobile for the peanut gallery
Quote:
Originally Posted by
jitahs
Apparently running the fender up btwn the mounts doesn't interfere with the bag.
the fender would be bolted on with 1/2" spacers, and at the peak still have some breathing room, not coming up into the space between the tubes
the 58mm knobby I have for it still has a slightly smaller OD than the fender
Quote:
Originally Posted by
jitahs
Ok I get it: the carried weight is born by the fork/axle/wheel, not by the steerer at all.
the cargo load, yes
but the rider, no
the majority of the flex in normal metal forks is concentrated right at the crown
and if you've seen many crashed forks, that's where they like to deform plastically too
sometimes there'll even be a bulge in the steerer a few cm above the crown race