Please explain triple clamp offset

[Detonator]

I'm trying to help a buddy wade through the sea of options when it comes to clamp offset, handlebar shapes, diameter, etc.

He's got a 2004 CR 250r coming in, and wants to swap the stock bar for a Renthal Fatbar (loves his current Tag, but dealer carries Renthal). My understanding is that he'll at least need a new top clamp to accept the 1 1/8" bar, but the dealer is prepared to throw in an "offset" Renthal triple clamp. Can someone explain what that is, and whether that would be of benefit to him. He's 5'9" and intends to do a mix of MX and woods.

Much appreciated!

 

[Shig]

Looking down at your triple clamps, you will see that the centerline for the fork tubes is slightly forward of the centerline for the steering stem. The distance between centerlines is the offset. I don't know the offset for the CR, but one of the changes people often made to quicken the steering of the early CRFs was to swap out the clamps for a set with a shorter, 20mm to 22 mm offset. You need to buy both the top and bottom clamps for this mod, then have a shop press the steering tube into the new lower. It will dramatically change the bikes handling characteristics, so I would do alot of research on the mod before swapping them out.

There is a chance that what the dealer really means is that they will give him a new top clamp with an offset bar position. This changes the bike's ergonomics, but leaves the steering geometry the same.

 

[2strok4fun]

This may be the wrong forum for that question.

what I think you are talking about is not the tripple clamp offset like Shig described, but a bar clamp off set that will allow the bars to be moved forward or rearward in relation to the tripple clamp, I could be wrong tho.

edit: I should have finished reading Shigs response, he answered both.

 

[Detonator]

Thanks, Lads!

The reason I posted this was because it made no sense to me that you could just slap on a differently angled top triple clamp, and expect it to line up with the stock bottom clamp. Knowing how cheap some dealers can be, my guess is also that they're offering an offset bar clamp, not triple clamp.

Buddy thinks he wants the MC bend for the fat bars. I found the profiles here http://www.bandcexpress.co.uk/pdf/RenthalHandlebars.pdf
If I'm reading this right, the MC bend height and rise are pretty flat. I'm wondering if this is the right pick for him. (This coming from a woods monkey...we run Hi-rise Mini bars and position our levers nearly horizontal).

 

[binder929rr]

you do'nt need to change the top clamp, it has clamp mounts on that cr so you just need to change the posts out with 1 1/8" mounts. cost like 40$ or so for them. bikes like the yz that the clamp is part of the top triple require a whole top triple to be replaced for big bars.

and offset changes how fast the bike steers. i can't tell you which way it goes, but the further out the forks are (increase in wheel base) the more stable the bike is at high speed but it doesn't turn as quickly and vise versa for the shorter wheelbase.

 

[elf]

[/QUOTE]and offset changes how fast the bike steers. i can't tell you which way it goes, but the further out the forks are (increase in wheel base) the more stable the bike is at high speed but it doesn't turn as quickly and vise versa for the shorter wheelbase.[/QUOTE]


actually, just the oposite is true.

 

[yz250flash]

I think binders reasoning is correct. Changing from a 22mm offset to a 20mm offset shortens the wheelbase and makes the bike turn fast. Going from a 22 to a 24 lengthens the wheelbase and makes it handle high speeds better but turn slower.

I always think of a chopper. It has a long wheelbase and may be stable at higher speeds but it takes a football field to turn one around.

Am I also confused?

 

[marcusgunby]

Its not really a wheelbase issue, its the amount of fork sits in front on the steering stem-it has many effects.Not all are good and not all are bad.

 

[bclapham]

for fatbars on the CR, you can just buy new oversized mounts for $60