john hawrylak

I am looking a steel frame, either stock or custom, for the following type of rides:
• Normal club rides
• Centuries & Brevets
• Light touring carrying only clothes (eat in restaurants, sleep in motels)
Note, racing and fast riding (>20 mph) and loaded touring are excluded.
• Want a front handle bar bag on rack like VO or Bethoud. Would carry tools and tubes in back saddlebag, but can see 5 to 7 lbs in the handle bar bag. Want stable handling with the HB bag, with minimal steering forces required
I am open to either 650B (38 to 42 or 700C (32 to 35 mm), depending on toe clip overlap and top tube length. Currently riding a 21” 1988 Voyager with 72° head angle, 74° seat angle and 347 mm wheel radius (27 x 1-1/4 at 31.3 mm width).

I did a long search on the VBQ site and determined a “low trail” front geometry is a good solution. However, the site gave very few specifics of the numeric values which makes for “low trial”.

I looked at the Boulder Bicycles site, which again gave some specifics about the All Road and Brevet models, but no “low trail” specifics. The seat and head angles are very close to my Voyageur.

A search of posts turned up Radonneuring Geometry in the Frame builders section. Very good info, but still questions exists.

Questions for the group:

1. What numeric values, in mm, are “low trial”? Any idea of the trail used by Singer or Herse Radonneuring models?

2. What happens when you ride a “low trial” without the HB bag? Previous posts state shimmy is likely with NO Hands. Does maintaining a grip on the bars eliminate the shimmy??

3. Any experiences with the Boulder models?

TIA & Merry Xmas

John Hawrylak
Woodstown NJ

Six jours

1) The lowest trail I have seen on a vintage French 650b frame is 10 mm. The highest is 50 mm. Average (and perfection, IMO) seems to be about 30-35 mm. I'd consider anything around 40 mm or less to "low".

The lowest trail I have seen on a vintage French 700c frame is about 35 mm. The highest was perhaps 55, but that was on a relatively modern Singer and may not count. Average seems to be about 40-45 mm, and I'd call that about the limit for a working definition of "low" trail.

2) Low trail bikes, in my experience, can get a bit nervous without a handlebar bag. This may or may not include shimmy at certain speeds. I've ridden low trail bikes that, without front bags, did not shimmy, or shimmied only with one hand off the bars, or shimmied only with both hands off the bars. I've never ridden one that shimmied with the top tube clamped between the knees. I know of no way to tell whether a particular bike will shimmy, but I do know that lower trail bikes are more likely to shimmy than are high trail bikes. In my experience, 650bx38-42 bikes will probably be stable unloaded if trail is at least 35 mm, while 700cx27-30 will probably be stable unloaded when trail is at least 45 mm. Trail figures lower than those make the bike a "loaded handlebar bag only" design, unless you don't mind paying the bike a lot of attention. And trail figures higher than that still work reasonably well with a loaded handlebar bag - so if designing a bike with both scenarios in mind, I'd opt for the higher end of the "low" trail range.

3) I look forward to hearing about them.

balindamood

You are going to spend some money on a 650B bike, but they do generaly have less trail. I would classify any 700c/27-inch wheeled bike with less than 50mm of trail moving towards the lower end, certainly below 45. It has been my experience that trail started to grow through the 1970s, with everyine seeming to land in the mid-50's by the mid 1980's. Many 1970's sport touring bikes will have a trail under 50mm. The only bikes that I am aware of by the early to mid eighties with some-50mm trail are generally loaded touring bikes (with some exceptions like the Specialized Expedition). I have found these bikes to be a tad squirly unladen, but settle right-in nicely with a moderate front load (40-45 mm).

Personnaly, I think your best bet would be an 1983 or older Trek 500/600 series. Depending upon wheels/tires, you will have a trail between 46 and 53mm. There are generally good riding bikes and can still be found at a reasonable, well kinda-reasonable price. Your other option are most 70's sport touring bikes, particularly those of European descent.

redxj

I have a few low trail bikes. My brevet ridden Nishiki Seral is in the lower-mid 40mm trail range and rides great with a front bag. I have wanted to do more long rides, but have only done a 200k on it. It is a jumbo sized (62cm) and I do get shimmy trying to ride no handed. Clamping the top tube with my knees and that goes away. I also have a Kogswell P/R 700c (jumbo 64cm) with almost identical numbers and that has the same shimmy problem. It is made with lighter tubing and I do notice it being a little quicker, spirited than the Nisihiki.

The last is a recent build and so far has only had a trip up to the store to pick up a case of beer. I built a very low trail (26mm) Porteur bike using an 84 Schwinn Le tour in a very small 26" size! I used the Electra Ticino fork which has 80mm of rake. Electra is selling the forks for $100 until the end of the year on their website. They have them in 1" and 1 1/8" with or without canti posts. The steerer tubes are super long (almost 12"/300mm) so they will fit very big bikes. Because of the large amount of rake a bike with a standard 73 degree head tube is going to be too low I think.

repechage

The above is a pretty good synopsis. For all the "low trail" descriptions there is some voodoo in the lack of full description. I equate it with many modern web sites of mfgs. where the key numbers are not given or better yet, the graphic design guy provides a questionable direction of measure, such as rake parallel to the ground...

fubaru

This blog, by the publisher of Bicycle Quarterly should help

RFC

Thank God. An intelligent discusson on C&V. I have been confused by this subject. Could someone define the nomenclature -- i.e., low trail/high trail.

unterhausen

trail needs a picture more than a definition in words, but if you draw a line through the steering column to the ground and measure back to the center of the contact patch of the tire, that's trail

balindamood

Without a little diagram handy showing exactly what trail is (you can find one in any number of locations), I can give you my opinion. High/Low is relative. Further, it is different for different types of bikes and tire sizes. If you consider 700/27-inch wheels, it seems that the line between high/low is about 50mm or so. Most bikes considered to have high trail (road-racers, anything from Rivendell, others) seem to have trail figures closer to the mid-50's to nearly 70mm. Older sport-touring bikes, most loaded tourers, and particularly older European bikes, all have trail numbers under 50mm, with the lower numbers approaching the upper 30's.

Most 650B bikes being built today also seem to be low trail versions 40mm and under. To me, it is because they are trying to resurect older French designs. These older designs (which used lower trail figures accross all wheels sizes) also supposedly considered bikes with a higher front load. I have other personal opinions which may explain some of this, but I donot have a blog, publishing company, bike brand/manufacturing company, or write for the industry press, so it doesn't matter. Basically the dividing line between high/low trail for 650B I would put about 45mm, maybe 50.

For mountain bikes, trail numbers are much higher. The older bikes (pre 84-85) generally used trail numbers well above 70, some even 80 or more. As the designs developed, the trail numbers dropped to the low to mid 60's by the early 1990's. Enter suspension forks, and things go to hell for about 10 years as everyone tries to out-gimmick everyone else. Somewhere amongst the BS, the forks started to get refined and the trail number seem to average in the mid-60's again. For 29'ers, we are back up around 70 again. In this case, they are all reltaively high. The dividing line between high and low is probably again 50-55mm. Again, I have my own theories why things have normaized at a higher trail values.

So; if we accept that current 650B offerings generally are being built around low-trail designs, and that ATB;s are being built about high trail designs, and we use road 700c/27-inch bikes to consider the broader spectrum, I (at least) conclude that the 50mm +/-5mm is the hazy, grey line between high and low trail. Tire size (width) will affect this a bit.

Just my thoughts.

Captain Blight

My old, lamented Centurion Lemans ('81-ish) had a measured 38mm of trail with 27x1-1/8 tires. It rode fine no-nands, right on down to walking speed over old brick paving. Eerie, really. Never did use a handlebar bag with it.

Citizen Chain has these frames NOS for IIRC $125+S&H.

john hawrylak

Thanks to 7 responses. I have a much clearer idea of where low trail is for 27/700 & 650B:
for 27/700, low trail appears to be 45 to 50 and less. Cpt Bligh reports no problems at 38 mm on 27x1-1/8 tires
for 650B, low trail appears to be 30 to 35 mm or less.
Shimmy appears to be the problem when trail is low. Corrected by knees on top tube.

John Hawrylak
Woodstown NJ

balindamood

I disagree that shimmy and trail are related, although I can accept that if there is a shimmy problem, it is more pronounced with low trail.

john hawrylak

Balindamood, I agree with you. I over simplified about "shimmy" in the response. Looking back, the sentence on shimmy should have been left out.

John Hawrylak
Woodstown NJ

Six jours

Actually, I'm quite sure that shimmy and trail are related. Low trail is obviously not a guarantee of shimmy, but low trail certainly increases the likelihood, in my experience.