Sunday, December 17, 2006

Making the Perfect Bike

In the last year or so, there has been a bunch of real and virtual ink spilled on the merits of low-trail bikes. The catalyst for all of this is Jan Heine, who publishes "Bicycle Quarterly," which in my opinion, is the best bike magazine around by a huge long shot.

Anyway, Jan's a huge proponent of low-trail bikes. "Trail" has to do with the front end geometry on bikes. It's the result, mainly, of head-tube angle and fork rake. A low trail bike tends to feel a bit "twitchier" compared to high trail bikes, which feel more stable. These are all feelings, and likely, riding any basically normal bike for a couple blocks will result in the rider making adjustments. So... you'll get used to any of these bikes. And "twitchy" has a negative connotation I guess. So, maybe "lively" is a better word?

The majority of production bikes sold today have high trail. In some cases, like with my 1991 Bridgestone RB-T, the trail is in the middle: not really low or high. In fact, I don't know of any low-trail production road bikes by any manufacturer. I'm not sure why high trail bikes have now become the norm. Apparently, most French bikes up to the 70's or so were low-trail. English bikes tended to be high trail. This makes sense when you consider where the cyclists in these countries tended to carry a load. Bikes optimized for front-end loads perform better (easier to go no hands, quicker turning, etc) with lower trail. Apparently, French riders/cyclotourists tended to have front bags mounted above the front wheel. English riders were big on saddle bags. Loading up a high-trail bike with a saddle bag makes for a smooth ride. My high-trail Atlantis excels with a fat load in the back. It does well with a load up front too, since high-trail bikes are OK with loads up front, they are just better with loads in the rear. My mid-trail RB-T is a nightmare with a load up front. Just awful.

Anyway. I picked up a 1983 Trek 520 about a year ago and let it sit around. This bike is a low-ish trail bike with standard diameter tubing and a geometry very similar to the French bikes of old. My buddy, Alex, who lives in Seattle has the same bike. I actually spent about 40 miles or so on his Trek when I realized how much fun it was to descend on. In addition, the bike felt just wonderful on climbs. Very similar to the feel of my RB-T. I had a very hard time figuring that one out. I assumed it was the shorter chainstays. But in measuring them and comparing them to my other bikes, the logic didn't add up. It turns out, the standard diameter tubing was the reason climbing and accelerating felt so wonderful. The majority of steel bikes produced today use over-sized tubing. Apparently, as diameter of steel increases, the stiffness increases exponentially. So, that "thing" I was feeling was flex. Or what Jan Heine calls "planing." Whatever. It's real and when I'm on an bike with OS tubing, that "thing" is not there. By the way, I'm in no way a fast, racer-type rider. So feeling this "thing" was a new experience for me when I first rode my RB-T. The "thing" combined with the quicker handling on descents was a huge deal when I rode the 520.

So, I came to the conclusion that what I wanted was a low-trail bike made with standard-diameter tubing. There is no production bike today that fits this. Kogswell is dang close, and I've riden the P/R about 50 miles. But when riding the P/R, I didn't feel that "thing." My guess is that it's the OS tubing, but maybe not, because there is a very vocal group of P/R lovers on the Kogswell mailing list that absolutely love the bike. Maybe it's all in my head.

Anyway, the 1983 Trek 520 is just about the right bike, but it is missing a lot of key components that I must have in a bike. The main ones were the ability to fit fat (well, bigger than 28mm) tires with fenders. I also have a thing for canti brakes since they just make sense to me in so many ways. The 520 had low trail, but not low enough. I wanted 40mm of trial, as that's the "magic" spot according to those who I trust. I also wanted the bike to be an everything bike: it must haul a good load comfortably; it must be good for all day rides. So, I decided to take the bike to local frame builder Hairy Gary and have him re-work it. Here's the list I gave him:

  • rake forks to 58mm (this will result in 40 mm of trail)

  • spread rear triangle to 132.5

  • braze-ons: water bottle mount to seat tube; 3rd water bottle mount under down tube; cantilever posts for 584 wheels; pump peg; attachment points for mini-rack on front fork; down-tube shifter mounts; rear brake cable stop bridge for canti-brake; rear-rack (chain stay) barrels; add'l eyelet on front fork for rack (on front side of fork dropouts)

  • strip/paint

He's also brazing me a custom rack that I can attach (sans tools) to the Nitto mini rack I will have on there. The custom rack will be a big-ass platform that I can strap big stuff too. Like a giant Wald basket. Or a huge package. Or who knows what.

So, he's so close to being done. The pictures here show where he was at this morning. Hopefully he's done with the fork now and the couple other bits. With some luck it will go to the powder coat guy this week. I asked him to surprise me on the color. Sparkles are good. Pink would be too surprising. Other than that, go for it.

Seeing the frame in the nude with flux and brazing goo on it really got me excited. I have the bits I need to build it up: typical used 90's mountain-bike parts and fenders and a B-17. I'm ready.


jim g said...

Nice! Can't wait to see the finished results!

Kaptain Amerika said...

I'm a little late on this one, but I just acquired an '83 520 (would've preferred 620 w/ 531, but 501 is fine and tough for rough riding) for the same "thing," SD tubing and low trail for the awesome feel of planing/flex. This will be my pure 700C rando (I have a 650B campeur), and with 33.33 Jack Browns the trail will be 49. According to Jan, "low" trail ends around 50, but classic rando geo is around 52, and the front rack and rando bag loaded will weigh no more than 10 lbs, but if/when I run front panniers too that could take the total to as much as 30ish lbs. My gut is that it will be fine, and that the trail is low enough for </= 10 lbs and may be the sweet spot for a rando bag, per le constructeurs of old. But I'm wondering about your experience with the rerake to the advised sweet spot of 40. How much did it lower your BB and dip your top tube? Is it a big difference handlingwise? Also, do you have a Flickr page? And how the hell did you get all that for $300?! Talk about a deal... Thanks!

John Speare said...


- In my experience, mid-trail (about 55mm or so) is the "death zone" for handling with a front load, even a light rando-type load. It just destroys the handling. I'd say 49 is pushing up against that neighborhood.

- 40 has become my sweet spot for fornt load. That was initially based on some of the testing that BQ did, and I've verified for myself on a number of bikes where I"ve dialed in the front end to hit 40mm.

- for unloaded, spirited riding on trail or road, i prefer mid-trail (about 55) with no load of course.

- web site here:

- you can search this blog for a few different low-ish trail configs that I've hacked (trek 720, rb-t, Rb-1, probably others).

- The bb is pretty low on the 520. when I ran platform pedals on it, I clipped on the corners a couple times. If I had still had the bike, i'd only ride spd and put 165mm cranks on it.

- $300. If you look at the actual work that he did, this is pretty reasonable. For a good frame builder, with the right fork tools, the work here can be done in an afternoon. That price included a $100 powder coat. Plus, Spokane is a great value for that kind of work (compared to more popular bike towns like Seattle/Portland)

Kaptain Amerika said...

thanks, so it did drop the BB substantially. dunno if that's a good idea. so... why did you sell it?

John Speare said...

I sold it b/c it just didn't have as lively a ride as I was hoping it would have. It made a great tourer and porteur and all rounder. It was also a part trade for my cargo bike... about the same time, I built up another "urban" style front loader (RBT), which was lively/springy/fast -- so the Trek became redundant.

Kaptain Amerika said...

do you think it was the 501 vs. the livelier 531 of the 620 and up?

Kaptain Amerika said...

What's your perfect bike now?