Quick geometry question- Mtbr.com

1. ## Quick geometry question

For those of you who know, what what should the axle to crown distance be for a 100mm Reba when building a custom frame. I know that the drop out to crown is 510. To get the proper angles should the frame be designed around 490 or 485mm's That way the head tube angle is correct when you are sitting on it. Am I making sense?

Thanks!

2. Originally Posted by Law
For those of you who know, what what should the axle to crown distance be for a 100mm Reba when building a custom frame. I know that the drop out to crown is 510. To get the proper angles should the frame be designed around 490 or 485mm's That way the head tube angle is correct when you are sitting on it. Am I making sense?

Thanks!

You might want to consider the fact that when the reba is locked out the fork is usually at full extension with little movement at the top side of the travel.

3. From the master...

http://forums.mtbr.com/showpost.php?...13&postcount=3

Hope that helps.

LP

edit - For the new Dean?

4. Originally Posted by Law
For those of you who know, what what should the axle to crown distance be for a 100mm Reba when building a custom frame. I know that the drop out to crown is 510. To get the proper angles should the frame be designed around 490 or 485mm's That way the head tube angle is correct when you are sitting on it. Am I making sense?

Thanks!
M \$.02. Have the frame designed around a 475mm fork 468 covers an 80mm for (without sag) and 490 covers a 100mm fork without sag. No sag isn't realistic and neither, IMO, is a 100mm fork on a 29er.

475 is the best middle ground.

-tom

5. ## One or the Other

Here is my thoughts on it...

Unless you are building a full out race bike, build that thing around the 100mm fork not the 80. When going 100mm you may want a shorter head tube. 80mm forks and frame in the 26 world are slowly dissappearing. I'm affraid it could happen in the 29 world next. If I have another 29 built it will be a 100mm bike. I rode a On One 29 Imbred with a 100mm Reba for a week, that bike was more fun than any 29 I have ever ridden.
Unfortunately NO bike can be good at both amounts of travel, and No man can serve 2 masters.

6. Originally Posted by Enoch
Here is my thoughts on it...

Unless you are building a full out race bike, build that thing around the 100mm fork not the 80. When going 100mm you may want a shorter head tube. 80mm forks and frame in the 26 world are slowly dissappearing. I'm affraid it could happen in the 29 world next. If I have another 29 built it will be a 100mm bike. I rode a On One 29 Imbred with a 100mm Reba for a week, that bike was more fun than any 29 I have ever ridden.
Unfortunately NO bike can be good at both amounts of travel, and No man can serve 2 masters.

I have no desire to run an 80mm fork ever again. Been there done that. 100 is much better, I can run a good amount of sag and still have plenty of travel left.

7. Originally Posted by lanpope
From the master...

http://forums.mtbr.com/showpost.php?...13&postcount=3

Hope that helps.

LP

edit - For the new Dean?

Well whadda ya know....Walt and I were on the same page. 485 - 490 is what I was thinking too. It is for the new Dean. The old dean was set to run less sag, it was designed for just a bit less sag than I actually ran on the Reba. However, I was thinking that since the Rebas are a little tall I would figure on a shorter length anyway in case the White Bros. forks are truly the cat's meow (and they are about 10mm shorter). I just wanted to be sure that I was thinking straight. Since I have a chance to do it over again I might as well be sure there isn't something that can be improved.

Thanks everyone!!

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