Low trail geometry frames

[Kenn]

Has anyone tried a French-style low trail geometry frameset. There seems to be a lot of interest in these in the USA, and frame manufactureres such as Rene Herse, Boulder cycles, Soma, Rawland, Velo Orange etc. supply frames. Many seem to use wide 650b tyres and, according to Jan Heine in Bicycle Quarterly, they handle very well over rough surfaces and offer a high level of comfort on long rides while maintaining good performance.

Is this just a fashion trend in the US or do these frames really provide good performance and comfort without compromising stability etc. There also seems to be an issue with availability of suitable rims and tyres for 650b so are the 700c versions a better bet? it would be very interesting to hear from anyone who has real day to day experience of these bikes.

[531colin]

Theres some discussion of low trail hiding in this thread, over several pages........http://forum.ctc.org.uk/viewtopic.php?f=5&t=77786&hilit=AWOL&start=165

[Brucey]

Has anyone tried a French-style low trail geometry frameset. There seems to be a lot of interest in these in the USA, and frame manufactureres such as Rene Herse, Boulder cycles, Soma, Rawland, Velo Orange etc. supply frames. Many seem to use wide 650b tyres and, according to Jan Heine in Bicycle Quarterly, they handle very well over rough surfaces and offer a high level of comfort on long rides while maintaining good performance.

Is this just a fashion trend in the US or do these frames really provide good performance and comfort without compromising stability etc. There also seems to be an issue with availability of suitable rims and tyres for 650b so are the 700c versions a better bet? it would be very interesting to hear from anyone who has real day to day experience of these bikes.

Well I have no great urge to get a bike with yet another redundant tyre size..... or indeed another French bike ( s' funny how all the good ones are built from British tubes, ain't it...? ) but it turns out that I have already owned lots of trendy 'low trail' machines.

How so?

Well Just like ladies' hemlines, different trail values have enjoyed various phases of popularity in lots of places.

I've owned various Claud Butler bikes, a Witcomb, and several others (from the 50's 60's and 70s) which have all had much lower trail than is considered the norm these days. There were plenty of others available from other builders, too; for a mere 25 years or so, if you bought a Jack Taylor touring bike the standard fork offsets gave a low trail setup.

So it is IMHO a case of the Emperor's new /old / misappropriated clothes....

Deja Vu all over again....

cheers

[Kenn]

Thanks Brucey. The enthusiasm for this geometry seems a bit too close to evangelism, which I instinctively distrust. i tried a Witcomb myself in the 60s. Didn't realise it was low trail. Nice bike but not as good a ride as my first Mercian.

Cheers, Ken

[Brucey]

in fairness the mixture of a front load, fattish supple tyres, and a light springy frame with low trail isn't an altogether bad one by any means. But low trail frames;

-don't always suit everyone in the way they steer; an acquired taste perhaps, but some say 'not stable enough' instead.
- are unforgiving of rear only loads, light wheelsets, skinny tyres etc
- are unforgiving of any tiny frame alignment fault. [ I was never convinced that my Witcomb was quite straight enough, and the low trail made it seem much worse than it really was.]

It is fair to mention that if the wheelbase (and/or front centre) is set by toe overlap, then the frame can be built lighter with a shorter top tube if the trail can be set low. Likewise if the top tube is a fixed length, a low trail frame can be made slightly longer wheelbase/front centre if this is desired.

BTW although I've seen other Witcombs with low trail, it is by no means certain that they were all like that.

cheers

[531colin]

............. if the wheelbase (and/or front centre) is set by toe overlap, then the frame can be built lighter with a shorter top tube if the trail can be set low. Likewise if the top tube is a fixed length, a low trail frame can be made slightly longer wheelbase/front centre if this is desired..............

The above is true if you take say a 72 deg head angle 45mm offset design and make it "low trail" by increasing the offset to 55mm for instance.
However, if you set the front centre as above, retain the 55mm offset, and take the design back to medium trail by slackening the head angle to 71 deg, then the top tube is shorter than 72 deg 55 offset (for the same front centre)

[Brucey]

you are right of course; I should have said 'for any given head angle' in there or something.

Whenever I think about this for too long my brain starts to hurt....

cheers

[531colin]

............
Whenever I think about this for too long my brain starts to hurt.... ...........

Me too. In fact its the only clear indication these days that I still have a brain.....
I think if any of it is important at all, my point is that if short top tube is the design criterion, then I wouldn't immediately start looking at low trail in order to achieve it.

[Brucey]

I perused this the other day

http://threespeedhub.com/wp-content/uploads/2013/04/ClaudButler-Catalog-1933-UK.pdf

and the bike on page 8 appears to have an unfeasibly low trail value; it looks like about 1" or perhaps even less.



Is this about the least that has been spotted in the wild?

cheers

[fatmac]

I usually go for about an inch & three quarter trail, stable but not sluggish handling, if you have too little it will be hard to keep in a straight line, likewise if you have too much you'll end up with very heavy steering. I think you will find that 650B used to be fitted to old roadsters, when they were known as 26" x 1 1/2"

[breakwellmz]

I perused this the other day

http://threespeedhub.com/wp-content/uploads/2013/04/ClaudButler-Catalog-1933-UK.pdf

and the bike on page 8 appears to have an unfeasibly low trail value; it looks like about 1" or perhaps even less.



Is this about the least that has been spotted in the wild?

cheers

Nice`light`steering.

Puts me in mind of leading link forks for motorcycle outfits.

[Ayesha]

Yes.
A Peugeot PX 10 LE.
75 head ( 74 seat ) and seriously raked forks. 50mm IIRC.

Rides a dream.

But I very much doubt the new bikes today will come with a 52/42 chainset and 14 - 19 six speed screw-on block !
They'll have a 50/36 with 11 - 25 cassette. And be 6 lb lighter !!

I changed to a 52/38 with a 13 - 23 screw-on.