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-   -   More touring friendly fork question (http://www.bikeforums.net/framebuilders/484834-more-touring-friendly-fork-question.html)

Hocam 11-09-08 08:16 AM

More touring friendly fork question
 
Hello folks more knowledgeable than me,

Here's the short, how can I modify the surly cross check geometry to be more touring friendly by either re-raking a fork that's too tall or building a new one? In other words, do I want more trail or less trail for a more stable, loaded front end (loaded w/ about 25-30 lbs, on a low rider rack).

Here's the long version:

I have a slight conundrum in regards to my 52 cm surly cross check. Last year I crashed it, had a friend new to framebuilding braze a new, extra sturdy fork to replace the one lost in the crash and had a good friend at Bilenky "persuade" the frame back into alignment. This experience makes me love steel frames even more.

It turns out that my friend building the fork bought a fork crown that appeared identical to Surly's, but was in fact too narrow. So we changed to a different one, and forgot about the difference in blade length. That put me with a cross check with a fork about 1.5 cm too long, it slackened the angles out (IMO too much) and raised the stand over height higher than I'd like. Still, I did a 2,000 mile loaded tour last summer on it. It behaved -ok- loaded, I couldn't ride no-handed but it wasn't unstable.

I've since moved and found another new to framebuilding friend, who has offered to either re-rake my current fork or braze a new one.

So, if he increases the rake of the old fork, that will reduce my trail as well as offering some solution to the too-tall-fork problem, but will it make the bike more stable under a fully loaded front end?

If he brazes a new fork, do I want more or less rake from the stock cross check geometry?

Nessism 11-09-08 12:31 PM

Quote:

Originally Posted by Hocam (Post 7817408)
Hello folks more knowledgeable than me,

Here's the short, how can I modify the surly cross check geometry to be more touring friendly by either re-raking a fork that's too tall or building a new one? In other words, do I want more trail or less trail for a more stable, loaded front end (loaded w/ about 25-30 lbs, on a low rider rack).

Here's the long version:

I have a slight conundrum in regards to my 52 cm surly cross check. Last year I crashed it, had a friend new to framebuilding braze a new, extra sturdy fork to replace the one lost in the crash and had a good friend at Bilenky "persuade" the frame back into alignment. This experience makes me love steel frames even more.

It turns out that my friend building the fork bought a fork crown that appeared identical to Surly's, but was in fact too narrow. So we changed to a different one, and forgot about the difference in blade length. That put me with a cross check with a fork about 1.5 cm too long, it slackened the angles out (IMO too much) and raised the stand over height higher than I'd like. Still, I did a 2,000 mile loaded tour last summer on it. It behaved -ok- loaded, I couldn't ride no-handed but it wasn't unstable.

I've since moved and found another new to framebuilding friend, who has offered to either re-rake my current fork or braze a new one.

So, if he increases the rake of the old fork, that will reduce my trail as well as offering some solution to the too-tall-fork problem, but will it make the bike more stable under a fully loaded front end?

If he brazes a new fork, do I want more or less rake from the stock cross check geometry?

For one thing, more fork rake REDUCES trail, which makes the bike steer faster, so you can not just "rake out" the fork you have unless you want to speed up the steering quite a bit.

I suggest you have a new fork built, or modify the one you have by shortening it, to match the characteristics you want. If your framebuilder friend is good, you could remove the dropouts at the bottom and shorten the fork that way. Also, have him set the rake where you want before reinstalling the dropouts. Not an overly difficult task since you have a goodly amount of fork length to play with.

Good luck.

NoReg 11-09-08 02:40 PM

Part of the issue here is whether it is a good idea to get a low mileage frame builder to make you a fork. Sounds like your first trip to the well was pretty disastrous. It's amazing that even some big name guys don't make them. I would probably try a new surly fork, XC or LHT if workable, or a Nashbar, or a Kogwells with all their options. Or just something from QBC. Those are all stock and if you have the right size available would probably work nicely.

I want to try out some fork geometry changes to see what happens. However, I am not convinced it's smart to do, just based on the fact I get good results with rack changes and maintain handling. I like the idea of an uber stable front steering, as most of my touring plays into that, Cadillac kind of stuff. But why give up the steering when the stability can be achieved through the load. You can have it all, notwithstanding a recent thread on FF. Your cool bet might be to get a standard fork, and pay a newbie builder to make you a better rack. Less likely to get you zapped in the process. Presumably if the new builder can do this kind of work, he has the answers on these questions.

My touring bike doesn't steer hands free, and I put it down to alignment problems in the price range in question. I hope to correct that, because I don't remember a problem with earlier bikes I had.


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