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Discussion Starter #1 (Edited)
Here's the offical el patron specs.

Could someone double check my math? At first I thought I would fit perfect on the 18". I'm currently riding a 23.25" top tube on 71/73 geometry. (med racerx 100)

As I looked closer I noticed the seat angle was pretty steep. So to get the proper position over the BB I'd prolly need to run a setback post. This would then increase MY effective top tube. I calculated about a ~.6" increase. So for me to compare apples to apples I need to add 0.6" to the posted El Patron tt length.

So now the 16" bike seems to be my size. Am I missing something?

Now on to head angle. The 29er forks are long. My current 26er fork is 470mm. An 80mm reba 29er is 490mm. This would cause a difference in fork offset of 6.5mm. Will I notice this? I noticed "floppy" steering on a ti racerx 29er I demod last month. I don't know what the HA was tho.

I'm thinking if I want the bike to steer the same as my current one I'd need the 29er to be about 71.8 deg on the head angle to have the same fork offset.

3rd concern is the relatively high BB. High in respect for a 3" travel xc bike. Is this something unique to 29ers?

I'm stoked about getting this bike. Just want to make sure there are no suprises. Thanks.
 

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xl_cheese said:
So for me to compare apples to apples I need to add 0.6" to the posted El Patron tt length.

This would cause a difference in fork rake of 6.5mm.

I'm thinking if I want the bike to steer the same as my current one I'd need the 29er to be about 71.8 deg on the head angle to have the same fork offset.

3rd concern is the relatively high BB. High in respect for a 3" travel xc bike. Is this something unique to 29ers?
I agree you need to figure out where the saddle will sit and calculate from there your ETT.

Your use of rake and offset are confusing me:skep: Not how I would use the terms. Offset is how far forward the dropouts are from the steering axis. Rake is a motorcycle term that I don't know the definition of? Is it the same as head angle, or the same as offset?

Finally, yes, with Sherwood's swingarm design and an uninterrupted seat tube, the BB has to be higher and the SA steeper than for a comparable 26" bike to get wheel clearance for the suspension travel.

The El Patron will rip, and I doubt you will find anything to worry about once you ride it. Run an 80mm fork and enjoy.
 

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What's that about fork length? Bike angles are always based on a given fok length. with other forks, angles differ. Rake is associated with a fork, not bike.
The fork length is provided, 487mm, sounds like 100mm travel after sag. You could get an 80mm fork to speed ahndling up, but the seat angle would get steeper still, towards 76º.

>I'm thinking if I want the bike to steer the same as my current one I'd need the 29er to be
>about 71.8 deg on the head angle to have the same fork offset.
Err, the other way around. Fork offset is more or less fixed (unfortunately), so to get the same TRAIL FIGURE, a 29"er indeed needs a steeper head tube angle.

You're on the right track about setback and all. But I think 2º diff in STA is worth more like 1" measured at the seat.
But you forgot the most important thing : stem length.
Unless you're married with your stem, think about what stem length would suit the bike best. Hint : everything between 50 and 130mm (based on broomsticks and risers) is known to work just fine for XC riding/racing, as long as the fit on the bike is correct for the rider's riding style. Heck, city bikes effecively run a negative stem length, the hands are behind the steerer. City bikes handle fine.

Hope this helps,

Happy trails,

J
 

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Discussion Starter #4
Enel said:
I agree you need to figure out where the saddle will sit and calculate from there your ETT.

Your use of rake and offset are confusing me:skep: Not how I would use the terms. Offset is how far forward the dropouts are from the steering axis. Rake is a motorcycle term that I don't know the definition of? Is it the same as head angle, or the same as offset?

Finally, yes, with Sherwood's swingarm design and an uninterrupted seat tube, the BB has to be higher and the SA steeper than for a comparable 26" bike to get wheel clearance for the suspension travel.

The El Patron will rip, and I doubt you will find anything to worry about once you ride it. Run an 80mm fork and enjoy.
yeah, maybe I'm not clear on the definition of rake and offset. At any rate from what I can tell the axel will stick out 6.5mm further on the el patron as compared to my current bike. That's using numbers for an 80mm reba fork.
 

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Keep in mind

that you can relatively tune the HT angle by increasing changing the reba travel between 80/100mm and by what size tire you run up front. Not knowing what A to C leght sherwood is assuming in his HT angle calc you might ask um..
 
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