View Full Version : Another Trail Question
FierteTi52
12-30-2005, 10:32 AM
71* HA with a 50mm fork rake = trail of approx 6.4
72* HA with a 43mm fork rake = trail of approx 6.5
The slacker HA with the longer fork rake produces a longer FC, reduces potential TCO, and lengthens wheelsbase. What other factors does a builder consider when designing front end geometry. In otherwords, there are several ways to acheive a desired trail. How would the two examples with similar trail affect the way the bike handles?
Thanks,
Jeff
e-RICHIE
12-30-2005, 10:52 AM
71* HA with a 50mm fork rake = trail of approx 6.4
72* HA with a 43mm fork rake = trail of approx 6.5
The slacker HA with the longer fork rake produces a longer FC, reduces potential TCO, and lengthens wheelsbase. What other factors does a builder consider when designing front end geometry. In otherwords, there are several ways to acheive a desired trail. How would the two examples with similar trail affect the way the bike handles?
Thanks,
Jeff
the first example would yield a more stable ride
by dint of the longer front end yielded, all other
variables staying unchanged.
The longer FC will also reduce the percentage of weight on the front. Whether that's good or bad depends on the balance.
Toe overlap wouldn't usually be a major consideration.
slowgoing
12-30-2005, 01:18 PM
Toe overlap is a huge issue with smaller frames.
Toe overlap is a huge issue with smaller frames.
Toe overlap is often unavoidable, if the TT length is short enough. Unless most of your riding consists of doing figure eights in a parking lot at 5 mph, it's NOT a problem. Cornering at normal speeds does not require turning the wheel any significant amount.
If you have toe overlap, you have to be smart enough to quit pedaling if you make a slow U-turn and watch your foot position when you take off from a dead stop.
Folks with large feet may have toe overlap with just about any frame they buy.
It wouldn't be common to add several centimeters to the front center, just to cure the overlap, if it fouls up the bike's weight balance.
e-RICHIE
12-31-2005, 09:58 AM
It wouldn't be common to add several centimeters to the front center, just to cure the overlap, if it fouls up the bike's weight balance.
agreed. front center dimension is "balance" issue and it is either
a chosen or a resultant measurement depending on your approach
to design. making it a certain length "just" to avoid toe overlap is
something i've never heard of.
Fortunately I ride bikes in sizes that never produce toe clip overlap, but it is a long-standing tradition in the building of French randonneurs that there is never TCO, even on the small bikes. Look at Herse and Singer, never ever. Whether folks think this causes a problematic ride for the solutions reached with rake and trail has never been raised by those lucky enough to own these bikes. I've never met an unhappy owner. I'd bet cash money too that Toei also never builds with TCO because of their link to those styles of building.
Everything is a trade-off, of course, and there's no singular solution.
Just a point without a point on a very snowy morning. (Three inches in the past hour.)
dbrk
Fixed
12-31-2005, 10:18 AM
bro is toe over lap a problem with track stands ?......no do it with no hands cheers :beer:
bro is toe over lap a problem with track stands ?......no do it with no hands cheers :beer:
Lemme clarify. I've no dispute here about TCO nor was I particularly commenting on FierteTi's bike. I also didn't/don't/never meant to hijack the thread!! I was just commenting had only two sorta' related points. First, I've seen guys going so slowly on randonneur rides that they might as well be doing track stands and so I hope they are riding a no-TCO bike. Second, I was down looking at my French bikes this morning and...well... French bikes are like the French: love'em, hate'em, they are charming, wonderful, and in many ways entirely unlike all other bicycles. French bikes are not good to compare in general--- and it has taken me years to reach that obvious conclusion. But they are also (perhaps like the French again?) little understood in America and brilliant at what they do. I don't know for sure what role TCO play(ed) in the design of Singer/Herse, et.al., my comment was simply that they design it out of any frame. What "cost" there is for that is another matter and, I think, everything has its cost, no? TCO is a byproduct of all sorts of considerations and bike design is a gestalt. If one factor is privileged over all others then the bike will be disagreeable. That's why I think the great French builders too thought of TCO as just one feature of the design, not privileging one but part of their who-cares-what-anyone-else-thinks notions of design. (I mean that when you see a Singer/Herse it looks pretty clear that they figure out their own stuff without the slightest concern for anyone else's ideas or opinions. Very French, no?)
I meant nothing contentious though I'm still, thank goodness, not entirely beyond that.
dbrk
Fixed
12-31-2005, 10:46 AM
bro you know about a million times more about bikes than i ever will. I only know what's in my little world sorry no disrespect ment .cheers :beer:
e-RICHIE
12-31-2005, 10:54 AM
TCO is a byproduct of all sorts of considerations and bike design is a gestalt.
THAT'S MY MANTRA!
bro you know about a million times more about bikes than i ever will. I only know what's in my little world sorry no disrespect ment .cheers :beer:
Oh no, no foul, no harm! I meant no criticism of anyone! I'd be happy to rip into something like the prospects for world peace but bicycles are way more fun and I steer as far clear of controversy these days as I can. (Personally I'd be in for a real disappointment if I found out I were not being wiretapped without a warrant given my penchant for French bicycles. You know, say a few nice things about old Simplex 5500 derailleurs and the next thing you know the NSA is listening...gosh, that _would_ be fun...)
If anyone did not find that mildly amusing then apologies in advance. And if anyone wants to see real cycling antics on a gravel driveway then make sure you visit the next time ol'Dirtdigger is here: the man has BMX skills on skinny tire road bikes...though I think the last time he was here I planted a strange French probe in his brain which only partly took hold and led to a fat tire Terraplane...a fine choice!! Almost French! Sorry Dave! :-)
oldschool icons 'r us too,
dbrk
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