Squishy Bike

[shirk]

Not much of this type of stuff posted around here so figured I would share.

This is my second frame, the first one was a hardtail. The original plans were to build a lugged commuter, then a couple hardtails, maybe a road bike then the full suspension. That plan got thrown out the window and I am moving onto build what I actually ride the most.

Info on the frame
650B
66 HA
75 SA
420mm chainstays
595mm stack
449mm reach
10mm bb drop
155mm of travel
160mm fork (old Fox 36)

Tubes:

38mm x 0.889 downtube from Aircraft Spruce
44mm TT head tube
34.6mm TT seat tube
35mm Nova 8/5/8 top tube
44mm TT head tube used for pivot housing

25.4mm x 0.889 uprights
25.4mm x 0.889 chainstays
19.05mm x 0.889 seatstays.

The main pivot will be using a 44mm headtube as the housing, I'll but two upper cups into it then use a section of 28.6 aluminium steer tube as the pivot axle. This allows me to get it done without and custom machine work and just regular reamers. I'll then clamp the rear triangle onto the axle.

I still need to finalize the dropouts and shock mount. Most likely will be just hand cut from flat plate.

[Mike Mcdermid]

Hey Brian I like it there's not too many on here's that build FS mtb

[Rayburn Shaun]

Looks good so far- don't know how you can cope with no shades though.... my eyes would be bleeding!!!

[shirk]

I've should pick up some of the old lady shields for over my glasses, I need the glasses to see find detail.

Previously I tried with a set of sun glasses over my glasses, but I couldn't pick up the temp colour right and cooked things. It doesn't help that I am red/green colour blind.

[jgrano]

Rad project. Looking forward to the updates on your progress.

[adarn]

Nice man.
I made a very similar bike last summer, it was fun to ride but I would recommend making sure you can pull off a decent chain line with your pivot position.
How did you come up with the pivot placement/linkage design? Also, why the 75* ST?

Good luck!

[shirk]

Adam,

I followed your thread on mtbr. I shouldn't have the chainline issues you had by using the 44mm headtube for pivot housing. With the inset bearings the total width can be narrower. I also plan to run this single ring 1x10.

The front pivot placement is a bit lower and inline with a 34t chainring compared to my current bike (Xprezzo Super-D). It will mostly get ridden with a 32t ring so it should pedal well with a decent amount of anti-squat.

No linkages. Just straight driving the shock off the rear triangle. I've been playing around with the Linkage program to find a placement that gives a linear leverage ratio. Shock will be a RS Monarch Plus so I can revalue to suit.

[adarn]

Sweet.
Have fun!

[blasdelf]

The main pivot will be using a 44mm headtube as the housing, I'll but two upper cups into it then use a section of 28.6 aluminium steer tube as the pivot axle. This allows me to get it done without and custom machine work and just regular reamers. I'll then clamp the rear triangle onto the axle.

genius!

which way are you going to set the preload?

[shirk]

genius!

which way are you going to set the preload?

The pivot axle will have a starnut presses into each end, preload can then be adjusted via either side.

[Andrew R Stewart]

I've should pick up some of the old lady shields for over my glasses, I need the glasses to see find detail.

Previously I tried with a set of sun glasses over my glasses, but I couldn't pick up the temp colour right and cooked things. It doesn't help that I am red/green colour blind.

I had an outside brazing "tent" for a while and it was so bright and flat lit that I had issues with seeing color change. Someone reminded me to 'watch my flux". I did and "regained' my sensitivity to the correct temp to braze. Andy.

[shirk]

Front tri tacked.


Checking clearance


Headset pressed in. I managed to ovalize the crap out of the 44mm headtube I am using here. Not sure if I squished it in the vise when cutting it to size or from heat. It looked so bad I didn't bother with reaming. I files the faces flat then just man handled pressing in the cup/bearing. You can feel the impact on the bearing, luckily the tight spot is beyond the travel of the rear tri.


Ghetto rear end fixture. It's just clamped on so see what kind of space I have to work with, need to use my drawing to figure out what angles and measurements will triangulate the rear axle into place.

Tonight I need to hand cut some dropouts.

My original goal was to have the bike finished in time to ride at the Whistler Enduro World series. Time is fast ticking away on meeting that goal. My better half wants me to have at least one pre-ride on it before hitting Whistler to pre-rode the EWS stages. Pre-rides start on Saturday...might have to take a day off work.

[thunderzy]

That's awesome

[shirk]

No laser cut, no water jet, no cnc, no mill. Just a hacksaw and files (okay and a drill).

I would really really rather be in the shop right now instead of behind a desk at work. I lost last night to a meeting so time is rather precious right now.

[Rayburn Shaun]

Coming out nice so far!

[Will Neide]

Looking good!

How much room do you think you'll have for fork crown/downtube clearance?

[shirk]

There will be an external cup headset pressed in, but according to my drawing things should be good with 2mm clearance.

I also missed my head tube angle and it's slacker than my drawing...so that should also add to the clearance.

[shirk]

So things have been moving along nicely...until this morning.

I messed up my design / drawing by making the chainstays too short.

I had fixtured the dropouts and started rough cutting my swing arm tube before realizing the error.


Notched toooooooo far.

So I cut the notch too far on the drive side. The picture is not exact it's a bit less than that after some adjustments.

I am thinking I'll patch over the gap with a sleeve. I don't have more tubing on hand and I'd like to finish this now that I am this far in. After getting this far I've realized that square tubing would make things easier and plan to build a 2nd rear end in a couple weeks.

But will it survive a months worth of not soo easy riding with that gap patched?

[Andrew R Stewart]

So things have been moving along nicely...until this morning.

I messed up my design / drawing by making the chainstays too short.

I had fixtured the dropouts and started rough cutting my swing arm tube before realizing the error.


Notched toooooooo far.

So I cut the notch too far on the drive side. The picture is not exact it's a bit less than that after some adjustments.

I am thinking I'll patch over the gap with a sleeve. I don't have more tubing on hand and I'd like to finish this now that I am this far in. After getting this far I've realized that square tubing would make things easier and plan to build a 2nd rear end in a couple weeks.

But will it survive a months worth of not soo easy riding with that gap patched?

Sounds like you're going to have an externally butted stay :) Andy.

[nspace]

This looks awesome so far.