Engin Cycles

[EnginCycles]

Drew,
This may have been addressed elsewhere, or even previously in this thread, but I've missed it if it has. I'm curious about your inspection technique - it seems most builders mount their frame to the table by the BB shell; you use bench centers and the head tube. Can you elaborate? If I may guess, it looks like you put the head tube between centers, insert a dummy axle with a center mark to check the rear end (with a height gauge?) and use an indicator to check the parallelism of the seat tube and the head tube. There's probably more to it, though! I've seen some photos of your inspection table with what looked like a collet chuck and a 5C expanding arbor - do you use that at any point in the inspection process (seems like a good way to get the BB square to the table, without relying on the accuracy of the facing), or is it all based on the head tube? How did you come up with your approach?

And thanks for documenting so much of your work, here and in your Flickr stream - it's nice to see photos of what different builders are doing, but it's even better to get a thorough explanation of why they're doing it the way they are.

Andrew

Andrew,
My process of inspection has evolved over the years and I have been using the system I use now for some time. I use the bench center to mount the head tube parallel to the surface. I trust this datum more than the BB shell since it has less distortion and the distortion that is there is not effecting the measurement as much as 4 tubes connected to a BB shell pulling it in all different directions. I have a post the stops the seat tube at the same centerline as the headtube and has interchangeable blocks depending on the size of the seat tube. This allows a permanent height gauge for the rear axle centerline. I use the dial indicator to check for seat tube twist and also check the face of the BB shell at 4 points (this I am actually making sure the high point is where I would expect it based on the distortion). I use a height gauge to check the inside flat of the drop out face and last I put a wheel check tool in the frame that rotates on bearings. Rotate and check at 3 or 4 spots to make sure it is flat. You can use the wheel check tool to make minor adjustments kind of like a Der. hanger tool.

I had an expanding collet that was used for BB mounting but I needed that chuck for my lathe after selling my South Bend Heavy 10 and took it off the table. I since made a standard BB post that I use to make minor adjustments to the rear end if needed.

I probably missed something but I think you get the idea. I feel my process is very accurate and trust worthy. The biggest thing I like is how repeatable it is. Just about every bike I pull out of the fixture is within .005" of the last bike I pulled. That tells me all is well. If it is way out I figure something is up and first re clamp everything. If still off then I back track. This might happen once a year and usually I scrap the bike.

Thanks for the kind words.

Cheers,
Drew

[e-RICHIE]

here's what i never understood re this method compared to a more conventional
approach (of using the bb faces calmped in a whipping post) atmo -

you set the head tube and then place the tube standard under the seat tube...

suppose it reads "off" based on your boundaries. how do you fix it (i.e. set it)?
and, even if, based on your system all is fine, what allows you to measure (and
rectify) the bio-mechanical axis - the one that places the rider's lower body over
the central movement - the reading that one normally checks by seeing if the seat
tube is perpendicular with the b.b. shell atmo? and - have you ever taken a frame
that read well using a conventional table method and reverse-checked it using the
procedure you describe here atmo?

Andrew,
My process of inspection has evolved over the years and I have been using the system I use now for some time. I use the bench center to mount the head tube parallel to the surface. I trust this datum more than the BB shell since it has less distortion and the distortion that is there is not effecting the measurement as much as 4 tubes connected to a BB shell pulling it in all different directions. I have a post the stops the seat tube at the same centerline as the headtube and has interchangeable blocks depending on the size of the seat tube. This allows a permanent height gauge for the rear axle centerline. I use the dial indicator to check for seat tube twist and also check the face of the BB shell at 4 points (this I am actually making sure the high point is where I would expect it based on the distortion). I use a height gauge to check the inside flat of the drop out face and last I put a wheel check tool in the frame that rotates on bearings. Rotate and check at 3 or 4 spots to make sure it is flat. You can use the wheel check tool to make minor adjustments kind of like a Der. hanger tool.

I had an expanding collet that was used for BB mounting but I needed that chuck for my lathe after selling my South Bend Heavy 10 and took it off the table. I since made a standard BB post that I use to make minor adjustments to the rear end if needed.

I probably missed something but I think you get the idea. I feel my process is very accurate and trust worthy. The biggest thing I like is how repeatable it is. Just about every bike I pull out of the fixture is within .005" of the last bike I pulled. That tells me all is well. If it is way out I figure something is up and first re clamp everything. If still off then I back track. This might happen once a year and usually I scrap the bike.

Thanks for the kind words.

Cheers,
Drew

[EnginCycles]

here's what i never understood re this method compared to a more conventional
approach (of using the bb faces calmped in a whipping post) atmo -

you set the head tube and then place the tube standard under the seat tube...

suppose it reads "off" based on your boundaries. how do you fix it (i.e. set it)?
and, even if, based on your system all is fine, what allows you to measure (and
rectify) the bio-mechanical axis - the one that places the rider's lower body over
the central movement - the reading that one normally checks by seeing if the seat
tube is perpendicular with the b.b. shell atmo? and - have you ever taken a frame
that read well using a conventional table method and reverse-checked it using the
procedure you describe here atmo?

I have a traditional whipping post on the table. It is used if there is a cold set needed. Most of my front tubes are heat treated so this is really not an option. The traditional post is used to move the rear stays. The HT method can be used to make small adjustments on the seat tube parallel compared to the HT. I do check the perpendicularity of the shell compared to the seat tube and also the centerline of it (a step I forgot to mention). I also double check my work at the very end once the BB shell has been faced. My method is primarily better for me since the HT is more trust worthy during the process. A BB shell that has been TIG welded or fillet brazed can have enough distortion that at 650mm away you would get readings that say you should chuck the bike. The HT as your datum rarely if ever tells this false information.

I have taken a few bikes that have come through the door and checked them and usually find error. The error is also usually within what I feel is fine so no telling if that is what the table at the manufacturer also said.

When I received my bike from Jamie Swan I checked the bike and compared to his info. I was within .001" of what he had said the bike was. When that happened I was very happy since it is a very non scientific way of checking your system.

Answer the question?

-Drew

PS- I spelled it centerline since I went to prep school in the good old US of A.

[e-RICHIE]

The HT method can be used to make small adjustments on the seat tube parallel compared to the HT.

how atmo?

I do check the perpendicularity of the shell compared to the seat tube and also the centerline of it (a step I forgot to mention).

during the method described, or elsewhere?
is it a starting off point for the seat tube, or measured at a different point in the sequence?

PS- I spelled it centerline since I went to prep school in the good old US of A.

appropriator!

[EnginCycles]

how atmo?


during the method described, or elsewhere?
is it a starting off point for the seat tube, or measured at a different point in the sequence?

appropriator!

The bench center is REALLY heavy and with the seat tube post centered on the seat tube you can lean on either end depending on which direction you want to move the tube. I do this when it is tacked and can move it up to .010" without effecting the tacks. Once welded what is the point of trying to move it? It won't move anyway without moving something else and then you are just chasing your tail.

I check the BB perpendicularity with a machinist square, height gauge and dial indicator all during the inspection that is done after tacking. It is verified by mounting the bike upon completion with a faced and prepped shell on the whipping post.


Another thing to keep in mind is I pull a complete bike from the fixture. I do not work in sub assemblies. I take a bike that is tacked at all points from the fixture to the inspection table.
-Drew

[edoz]

Andrew,


I had an expanding collet that was used for BB mounting

I seem to remember seeing this on your Flickr page, but can't find it again. Can you give a bit more info? I've looked for something that would work at Enco and MSC, but can't find one.

[EnginCycles]

I seem to remember seeing this on your Flickr page, but can't find it again. Can you give a bit more info? I've looked for something that would work at Enco and MSC, but can't find one.

Eric,
You need to turn the collet to your final spec. For the 68/73 1.5" sheels I started with this collet and for the pressfit 30 I started with a much bigger one. I turn them and leave a lip for a set height off the table. It was a good system and for use during the assembly it was more trust worthy than the faces but like I said I needed the Bison 5C chuck for my lathes and since I was using the HT as my main datum I figured I would just make a standard new whipping post. My standard post is made a bit different as well but by concept it is doing the same thing.

-Drew

[roguedog]

Is it just me Drew or do you seem to build a lot of small bikes? Every time I see one of your bikes they actually looked like they'd fit me :) which is a rare thing around here..

[EnginCycles]

Is it just me Drew or do you seem to build a lot of small bikes? Every time I see one of your bikes they actually looked like they'd fit me :) which is a rare thing around here..

I do build a good amount of small bikes. That road bike this week with the box lining has a 52.5cm top tube and is for someone around 5'6" short. I build a lot of 29R's for women as well. I do however build some rather huge bikes as well. Doing a 29R now for someone that is 6'4" and recently did a 29R with a 25.5" top tube.

The smaller 29R's are really the thing that gets people. As long as you are building the entire package (meaning fork and frame) there is little that can not be achieved in fit and design. I am a firm believer in the 29" wheel and always try to get the rider on the largest roll over capacity tire that works. Suspension is usually the killer. Why does a 5'4" woman that weighs 105lbs need suspension? It won't even work right and a 2.5" tire with 18psi will do just as much in damping the ride. Drop that 80mm of front end and all of a sudden the standover issue is gone. Combine that with building the fork and now you can really tune the ride characteristics. I might have gone off on a different direction with this answer?

-Drew

[Andrew Drummond]

Thanks everyone for the replies - it's given me lots to think about. They've made me really think through doing things in the right order and using heat and shrinkage to my advantage. At my day job, it's no big deal if something moves when it's welded - we just bend it back or mill it flat, and in fact plan on it. It's a little harder to keep things straight and square without that luxury!

Andrew

[EnginCycles]

Thanks everyone for the replies - it's given me lots to think about. They've made me really think through doing things in the right order and using heat and shrinkage to my advantage. At my day job, it's no big deal if something moves when it's welded - we just bend it back or mill it flat, and in fact plan on it. It's a little harder to keep things straight and square without that luxury!

Andrew

Andrew,
There are many ways to build a bicycle. I have come up with a method that works for me and I like to stick with it. I am always tweaking and willing to try different things but all in all the system remains the same.

Good luck.

Cheers,
Drew

[JoB]

Drew-

what are your thoughts on the dis/advantages of Alu vs. steel in mountain bikes? Are there advantages steel has over alu in your view, and are there advantages of alu over steel? If so, how do you overcome the latter with your steel frames? Thanks - you have some very interesting perspectives.

[EnginCycles]

Drew-

what are your thoughts on the dis/advantages of Alu vs. steel in mountain bikes? Are there advantages steel has over alu in your view, and are there advantages of alu over steel? If so, how do you overcome the latter with your steel frames? Thanks - you have some very interesting perspectives.

Aluminum has a place in the bicycle industry. It is and will always be the best option for components that are cold forged and the like. As a frame material it tends to have a life span of 5 years max and with real use (racing and abusing) it is around one season before you should really inspect it. If the aluminum bike is made to last longer you more than likely have enough material there that the same bike could have been achieved with steel. I like to make bikes for the worst case scenario. With MTB's the disc brake is the item that is very hard on bikes. Next is the long forks and the HT area. Bikes break it is just a fact of life. My goal is to avoid this as much as possible.

For me steel can be used to do anything I want. I can bend it, machine it and attach it in all kinds of ways to get an end result I am looking for.

Aluminum seems to be getting replaced even in the MTB world with carbon (at the high end level). More and more the uber light bikes are carbon and the basic bikes are aluminum. The facilities overseas have made a shift and they can produce quicker if the set-ups and what not do not need changing. All the high end road stuff is carbon. The mtb stuff has a higher degree of abuse but everyone seems willing to push that envelope. I feel I have made zero compromises with my design and the use of steel. The bikes ride great and can handle an incredible dish of abuse.

I tell all my customers that spending money on lighter wheels will ALWAYS be worth it and noticeable. I would be willing to replace 2 rims each year and run Stan's Crest rims since the rolling weight will be noticeable. My bikes are about 3/4lb heavier than an average aluminum frame. Nobody would notice this and in fact if we had the light wheels on the heavier frame and the heavier wheels on the light frame there is no question which would ride "lighter". The Edge (or Enve whatever you prefer) rims would be great if they did not require 15 strips of tape to work tubeless. The tubeless system is far better than an inner tube and a lighter rim (that Crest is really light and very close to a carbon rim).

Aluminum bikes will always exist but just do not do it for me (welding aluminum is kind of gross). There is a reason everyone compares bikes to steel. The stuff works and has lasted the test of time. There is no wonder material but based on the longevity of steel I think it is about as close as you can get.

Did I answer your question or prompt more?

-Drew

[vegancheesesteak]

I do build a good amount of small bikes. That road bike this week with the box lining has a 52.5cm top tube and is for someone around 5'6" short.

Stop calling me short. You're pretty much the same height as me. :P

[EnginCycles]

Stop calling me short. You're pretty much the same height as me. :P

Wow, you signed up to defend your honor! It is true we are both short. The bicycle world is not as difficult to deal with at much as the textile world. Even my work pants need to go to the tailor.

-Drew

[vegancheesesteak]

Wow, you signed up to defend your honor! It is true we are both short. The bicycle world is not as difficult to deal with at much as the textile world. Even my work pants need to go to the tailor.

-Drew

I've been lurking for a bit to check out the Friday Night pics...

This leads to a good question and an extension on an earlier question about the smaller bikes you've built....

You've got a really dialed in 29er geometry, the bikes love to climb and handle tight twisty single track awesomely so I guess you have the weight placement where you want it. What do you feel is the limit on rider height for different kinds of 29ers before you start to sacrifice handling? For example rigid, front suspended and full suspended, whats the minimum height to ride?

[EnginCycles]

I've been lurking for a bit to check out the Friday Night pics...

This leads to a good question and an extension on an earlier question about the smaller bikes you've built....

You've got a really dialed in 29er geometry, the bikes love to climb and handle tight twisty single track awesomely so I guess you have the weight placement where you want it. What do you feel is the limit on rider height for different kinds of 29ers before you start to sacrifice handling? For example rigid, front suspended and full suspended, whats the minimum height to ride?

Nick,
I think part of it is how I always think of the bicycle as a complete entity and never just look at the frame. The stem, the seat post that will be used and fork all have something to do with the correct position and how the bike will handle. Sizing is tough since it is not just height. Starting small I think 5'4" is the smallest for a rigid specific bike that has a reverse curved top tube. The front suspension bike can be done for some people with a 30" inseam and I could even squeak by for someone shorter by utilizing the reverse curved top tube. The full suspension bikes are very hard since they have very high BB's and most run 100mm of travel. You can make some adjustments but once you drop that high BB I think the bike becomes less useful. These are better left for the 32" inseam and up folks.

Generally, I think standover is highly overrated. It could be my cyclo-cross history but it just does not matter if you don't have miles of standover on a bike. The idea is the bike makes it up the hardest of the inclines. Bikes with tons of seat post exposed bother me more than bikes with little standover. The cross bike is a great example of where standover is completely useless. The only time you will be standing over that bike is at the start line. Side dismounts don't require standover, shouldering a bike however is much easier with shoulder room.

FWIW Nick is my webmaster and an incredible graphic designer. He is also behind some of the work that helps promote NAHBS.

-Drew

[EnginCycles]

Shameless self promotion.

This is a HUGE file and if your computer is not up to the task be prepared. Still under construction but I am working on a full interactive tour of the shop:

krpano.com - _MG_0020 PanoramaunTWISTed8bpcplain3JPEG

Enjoy.

[Archibald]

Shameless self promotion.

This is a HUGE file and if your computer is not up to the task be prepared. Still under construction but I am working on a full interactive tour of the shop:

krpano.com - _MG_0020 PanoramaunTWISTed8bpcplain3JPEG

Enjoy.

OK, that is cool. How is that done?

[cement shoes]

that's tight, Drew.

Looks like a Flash extension of some sort, probably some ActionScript to control the buttons.