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Old 12-12-12, 03:50 PM   #1
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I want to try a low-trail bike

I don't know where to find a low-trail bike for an extended test ride (weeks?). I'm actually thinking about bending more offset into one of my spare forks and installing it -just so I can try it out. Somebody stop me.
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Old 12-13-12, 07:12 AM   #2
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I can neither help nor stop you; but I have to ask, WHY???
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Old 12-13-12, 07:34 AM   #3
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Experimenting with geometries. Lower trail supposedly offers better handling for bikes with a front load. But too little trail gets "twitchy." Shy of commissioning a full custom bike ($$$), there doesn't seem to be any way of trying it out first. Nobody makes stock forks with higher offset (I need ~55mm) or stock bikes with lower trail.

And, actually, as I do the math, it appears shrinking the wheel size (from 700c to 650b) may help get me much nearer to "low trail." I'll try that first.

(Trail: how far behind the steering axis is the contact point of the front tire.)
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Old 12-13-12, 07:57 AM   #4
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dbg,
I am not sure which of your bikes you want to try the set back axle on, if it is one with a modern steerer tube set up maybe you could find a Cannondale SAVE fork like the CAAD 10 models have and ride it. My 10 4 has the back offset front axle like you are suggesting, I believe. If it is an older bike with a threaded steel fork and steerer tube I would think that a fork from a criterium or track bike would come closest to the geometry you want to try. These would be the straightest tubes that I can think of so their trail would be in line with your thinking. Just a thought, hope you find what you are looking to try out.

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Old 12-13-12, 11:25 AM   #5
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Shy of commissioning a full custom bike ($$$), there doesn't seem to be any way of trying it out first. Nobody makes stock forks with higher offset (I need ~55mm) or stock bikes with lower trail.
There are some low trail production frames out there, so a full on custom build would not be necessary. Or maybe get a custom fork built to work with your frame. You could post in the framebuilders forum to see if that's possible.

http://store.velo-orange.com/index.p...ndo/rando.html
http://www.rawlandcycles.com/store/i...intItemID=3960
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Old 12-13-12, 12:42 PM   #6
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There are some low trail production frames out there, so a full on custom build would not be necessary. Or maybe get a custom fork built to work with your frame. You could post in the framebuilders forum to see if that's possible.

http://store.velo-orange.com/index.p...ndo/rando.html
http://www.rawlandcycles.com/store/i...intItemID=3960
Most excellent links.
Velo seem to be out of stock on everything but 59 and Rawlands is maybe a bit too "square" for me (prefer slightly longer top tube than seat tube due to body dimensions). I don't mean to be picky but I want to minimize experimental $$. Also I'm in the size range where toe overlap can occur-- which I've come to dislike and want to avoid.

My problems don't stop there. I want to shift item carriage to a front bag but I don't want to give up brifters. And I ride on some trips where others are stripped down and super light (and younger than me), so I don't especially want to go all heavy. But these are fun puzzles that I happily drift off to sleep every night thinking about (which is much better than work stress).
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Old 12-13-12, 01:51 PM   #7
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dbg,
I am not sure which of your bikes you want to try the set back axle on...
Actually, what he's considering is a fork with more offset in the forward direction to reduce trail. A reverse-raked fork would increase trail. It sounds funny describing it that way, but if you draw it out, it makes sense.

EasyRacers, which used to sell plans for building a TourEasy, included how to build a jig for bending a fork, since a TourEasy uses a fork with a huge amount of rake. The trick would be getting both legs bent the same, so the wheel sits in it straight.
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Old 12-13-12, 01:57 PM   #8
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Both my Folding bikes, Bike Friday P Llama , and Brompton, are Low trail..
I usually have a Load on the front wheel. .. panniers, or the Brompton T Bag

If you can cut a curve in a 4x4 with a band saw, and anchor the dropout, some how,
then you might pull off a re rake.

Last edited by fietsbob; 12-13-12 at 02:02 PM.
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Old 12-13-12, 02:38 PM   #9
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Actually, what he's considering is a fork with more offset in the forward direction to reduce trail. A reverse-raked fork would increase trail. It sounds funny describing it that way, but if you draw it out, it makes sense.

EasyRacers, which used to sell plans for building a TourEasy, included how to build a jig for bending a fork, since a TourEasy uses a fork with a huge amount of rake. The trick would be getting both legs bent the same, so the wheel sits in it straight.
Okay, I understand what he/you are saying, now and this makes more sense than what I originally thought. I could not bring my mind to absorb the way it was worded. This is the second time I have reversed the trail measurement details, I need to write it on my forehead with a Sharpie pen I guess.

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Old 12-13-12, 03:16 PM   #10
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Here's a nice link for calculating trail:

http://yojimg.net/bike/web_tools/trailcalc.php
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Old 12-13-12, 05:51 PM   #11
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Okay, I understand what he/you are saying, now and this makes more sense than what I originally thought. I could not bring my mind to absorb the way it was worded. This is the second time I have reversed the trail measurement details, I need to write it on my forehead with a Sharpie pen I guess.

Bill
Don't forget to write it in mirror-image! (Or, it might be easier to just use paper.)
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Old 12-13-12, 06:06 PM   #12
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I build frames and have experimented with a bunch of different forks/trails trying for the "ideal" set-up for the French-style rando bikes that are undergoing a mini-renaissance. I'm not nearly as convinced that low trail is necessary for front-loaded bikes as, say, Jan Heine. I've ridden all kinds of bikes with front loads and find that moderately low trail works slightly better than other approaches. Really low trail feels unstable to me (remember that Jan is coming at this from a "performance" perspective rather than the more relaxed "touring" kind of perspective common to people carrying significant loads on their bikes - he may be looking for a more "responsive" bike than the typical randonneur rides) and high trail feels just slightly weird out-of-the-saddle, but not nearly enough for me to consider it a problem.

So I wouldn't feel as though it's critical to have a low trail bike to use a front load, if I were you.

If you really want to experiment, though, building a simple rake jig is pretty straight forward. This one is pretty typical.

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Old 12-13-12, 06:12 PM   #13
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This is an interesting topic (I'm looking forward to learning how this works out for you dbg).

The whole "low trail" kick appears to be gaining popularity with those involved with randonneuring and/or hauling items up front. Seems that most of those who try LT end up liking it, with or without a load up front (often after expressing initial doubts about it). 35-40mm trail seems to work well for many riders.

Longleaf Bicycles used to sell LT forks a few years back (@ ~ $90), but I don't see any on their site now. Meanwhile, I agree with your thoughts of trying LT out first with a 650B wheel change.

And ya, I too often get mixed up when talking bicycle steering geometry. This is due, in part, to my motorcycle background (rake = steering head angle in motorcycle terminology).

Good luck with your project.
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Old 12-14-12, 07:22 AM   #14
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David, I went through this whole thing, and I still am. I had a low trail (60 mm offset) fork built for my '84 Trek610, here in Ypsilanti, MI (well, next door to Ann Arbor) for a very reasonable price. Liking that, I bought a Terraferma 650b frame used, and I like it's ride, too. pm me and I can talk about the fork builder.
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Old 12-14-12, 12:08 PM   #15
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It is the Porteur mystique.. the quite heavy loads of bundles of the Daily Newspapers rushed from the loading docks
of the Publisher, to the street kiosks of the vendors, over the cobbled streets of Paris.. on delivery bicycles.

US doesn't even have sweet shop/news agents any more..
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Old 12-14-12, 12:46 PM   #16
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I'm actually sort of trying to solve two things with this geometry experiment. I hate toe overlap and my typical road bike size usually has it to some extent (56-55-54). Dropping to a 650b and pushing a little more fork offset in my current road frames reduces (maybe eliminates) toe overlap while also dropping the "trail." But I don't want a twitchy frame that shimmies on fast decents and I do like to "no hand" for brief stints to stretch the shoulders and back (and maybe dig snacks out of the rear pocket or put away sun glasses). So it really is a "try it and see" experiment. And I'll probably be attempting my own fork bending if it comes to that (sound like fun).

(This is how several other obsessives hobbies have started, however, including loudspeaker design in college and golf club design a little after college.)
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Old 12-14-12, 04:02 PM   #17
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Oh boy, first qcpmsame brings up MX racing (my left knee still hates me for this), and now dgb mentions "loudspeaker design" (I've got boxes of various drivers, x-overs, etc, going back 20 years). Then there's the RC fixed and rotary wing model stuff I've got stacked up about the place. Oddly enough, my most recent hobby is a tiny home recording studio setup.

It's a good thing that my bicycle hobby hasn't gotten to the point of being obsessive. I only have: 1 '75-'80ish road bike, 1 urbanized MTB, 2 ebikes, and 1 track bike (that I just built from the frame up). Nope, nothing "obsessive" to see here...
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Old 12-14-12, 04:58 PM   #18
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I had concluded (and wrote about) in the early 70's that separate subwoofers and satellites were the way to go --way before they were commonplace (they just made sense for a lot of reasons). I was also building long iron length golf clubs with early (small) metalwood heads in the 80's that were pretty much what we now call "hybrid" clubs. Both cases were too far ahead of their time to be of any use to me (but I still have a very early hybrid-like club that my playing partners referred to as the "iron woodie.") Obsessive hobbies are great for forming ideas.
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Old 12-14-12, 05:04 PM   #19
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How about variable trail? When I sit up and move more weight to the rear, the fork sucks in the offset to get more trail for no handing stability. And when I move weight forward the offset extends and lessens trail.
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Old 12-14-12, 05:12 PM   #20
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Sounds like you just need to get on to Fabricating something.. maybe put a rear Track dropout
on the end of a front fork, so You can move the axle in the front fore and aft.
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Old 12-14-12, 06:02 PM   #21
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I had concluded (and wrote about) in the early 70's that separate subwoofers and satellites were the way to go --way before they were commonplace (they just made sense for a lot of reasons).
That must have been really cool back in the day huh?

My biggest speaker design "challenge" was building a dual 10 inch 4 ohm 4th order isobaric push-pull band-pass sub box back in the mid/late '90s. This thing will still shake the place with an old 30-40 watts per chan AB amp driving it (I couldn't tune any lower than about 35Hz tho). You can run it 4 ohm dual channel, or as a single channel box at either 8 or 2 ohm. The only problem is that I have yet to find a reasonably priced amp (auto or home) that's rated as being 2 ohm stable. This thing served as my home theater sub for more than a decade.

Sorry for going so far off-topic on you...

Anyway, I seem to remember that many LT riders experienced more than suitable handling whether loaded and unloaded. But then again an adjustable/variable trail setup sounds like something that needs to be looked into...


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Obsessive hobbies are great for forming ideas.
The Wright brothers achieved the first powered flight while obsessively pursuing their flying hobby (I believe they were, first and foremost, bicycle mechanics at the time)...
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Old 12-15-12, 05:44 AM   #22
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I'm actually sort of trying to solve two things with this geometry experiment. I hate toe overlap and my typical road bike size usually has it to some extent (56-55-54). Dropping to a 650b and pushing a little more fork offset in my current road frames reduces (maybe eliminates) toe overlap while also dropping the "trail." But I don't want a twitchy frame that shimmies on fast decents and I do like to "no hand" for brief stints to stretch the shoulders and back (and maybe dig snacks out of the rear pocket or put away sun glasses). So it really is a "try it and see" experiment. And I'll probably be attempting my own fork bending if it comes to that (sound like fun).

(This is how several other obsessives hobbies have started, however, including loudspeaker design in college and golf club design a little after college.)
I know several here have talked about re-raking forks, but I had trouble getting a framebuilder to make this adjustment, which was why I had a fork made. YMMV.

What I found as a surprisingly nice way to test low trail was to get a Peugeot UO-8. Mine is a late-60s or early-70s. 55 cm seat tube (c-c), 46 cmchainstay, 61.6 cm front center (zero toe overlap), 72.5 degree head tube angle, 70 mm fork offset (and it does not look bent, to my eye). The trail calculates to 34.5 mm, and with a fat 700c (32 mm) it rides stable and supple, with good isolation of the rider from road shocks. No crit racing on this thing, but it's a great cruiser. The steering is very precise, but it takes effort do divert the bike. My higher-trail bikes tend to flop around when I climb slowly (I usually climb slowly!), but not the UO-8!

If brakes that would work well with 650 could be fit to those frames, they'd make a great 650 rando conversion because of that low trail. I'm not sure how the between-chainstay clearance works for 42 mm - I like to see an available width about 50 mm for the tire alone, and more for a fat fender.
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Old 12-15-12, 09:20 AM   #23
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I have a similar UO-8. Set up as a SS, it has always been my favorite ride. It just feels good. I recently abandoned it and was about to give it away because I wore out the BB and wasn't planning to go search for another french threaded BB. I'd better go measure that thing and maybe resurrect it.
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Old 12-15-12, 02:56 PM   #24
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I have a similar UO-8. Set up as a SS, it has always been my favorite ride. It just feels good. I recently abandoned it and was about to give it away because I wore out the BB and wasn't planning to go search for another french threaded BB. I'd better go measure that thing and maybe resurrect it.
You really might have trouble finding a Peugeot-sized cottered spindle, since I understand they had a unique diameter, though it's worth looking for. I'd look for a good older cotterless crank like a Shimano 600 6207 (or just anything in a single-ring variant), and install it with a V-O French-thread BB. Not sure how the lengths work out, but it IS French-threaded. Keep a good machine rolling.
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Old 12-15-12, 05:05 PM   #25
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My '74 Raleigh International met the OP criteria for the low-rake fork and geometry. it was definitely not a crit bike in any way, the long curved fork and relaxed geometry with the long wheel-base made for a very stable platform. I never had a complaint about the handling but I used it for fast club rides and training, no reason to need the "straight up" geometry or fork for my riding. I understand why you want to experiment with this geometry.

I'd buy it back if I could ever find it in a NY minute, no idea where the man that bought it went, that was in 1981. A Reynolds 531DB full tube set, including the fork, beautiful lug work and chrome socks front and back and Campy Nuovo Record drive train and hubs, Suntour Superbe brake set, man it was sweet, I didn't know what I had until it was sold and gone.

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