Buildng 29" rear wheel for Pugsly need help with Calc.- Mtbr.com

# Thread: Buildng 29" rear wheel for Pugsly need help with Calc.

1. ## Buildng 29" rear wheel for Pugsly need help with Calc.

I am going to build a 29" wheel using a Sram SL hub and Sun Rhyno Lite Rim. Does anybody know how to do the calculation to take into account the asymetrical rear end?

2. ## Wildfire

I know that Wildfire has built at least one set of 29" wheels, I had him build my large marges and when I picked them up I asked him about this exact application and he said it wouldn't be a problem. If you PM him or maybe re-post this in the Alaska board you will most definatly get an answer. Good luck

3. ## Run the calculations allowing for a 17.5mm offset...

If I remember things right, you can use the Dt Swiss website's calculator, but you have to factor in the 17.5mm offset.

*Ditto the idea to contact WildFire. He did have a post related to this in that forum. If that doesn't help, contact Surly at: Eight Seven Seven, Seven Four Three, Three One Nine One. I thought they had this subject up in their blog, but cannot find it right now.

**You could try e-mailing Slartibartfast or pm'ing him, he might be able to help out, as they've also done one recently.

Is this what you were referring to Bones??

Originally Posted by wildfire
Spoke Lengths

By my calculation, the ERD is 535. Using Sutherland's method the rim correction factor is -32. It gets weird with the offset drilled rim and offset frame though. I use the spoke length calculated for the non drive side on the drive side and subtract 2 mm from that to get the nondrive spoke length (assuming equal hub flange diameters) and it has worked out right on almost every time.
Have you seen the new QBP catalog? They did a new extrusion on the Large Marge and radically changed the shape with more spoke offset.

"Also, the ERD published for the Large Marge rims seems really off. All my spoke calcs have come out a good 2mm too long. I think my rims have an ERD of more like 532mm, not 536 as is commonly reported or 539 as Bob the Wheelbuilder indicated to me.
"
Last edited by Wildfire : 02-15-2006 at 11:36 AM. [QUOTE]

4. How do I factor in the 17.5 offset? Do I just add to one of the dimensions?

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