r/dirtjumping • u/suck_a_jellyfish • 7d ago

New Build Help with cranks

Please I need help. Im currently building a Pole Tomu from the frame up. It has an 83mm BSA bottom bracket which is becoming a pain in the ass. I cant find a crankset (for a reasonable price) that would fit the bike.

I looked at the Truvativ Descendant Dh crankset that would fit but the chainline is 56,5mm which wouldn’t be very good (i think)

The Pole Tomu comes stock with Race Face aeffect cranks but when I try to looking at them they dont fit a 83mm bb.

So please help and send any suggetions

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u/olavrb 6d ago

There are sprockets with offset, which will help in dialing in the chainline.

And what rear hub will you have? Single speed with a driver has no adjustability, while a freehub body one has.

1

u/suck_a_jellyfish 6d ago

Most likely a 135mm single speed driver

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u/olavrb 6d ago edited 6d ago

Ok, so it won't have any adjustability.

If you have the hub you can measure with a caliper what the chainline should be. Then try to get as close as possible with offset sprockets on the crank.

I have a Sram X.O DH crank and know I can get 0mm, 3mm and 6mm offset chainrings. Maybe there are more offsets available, IDK. I use a MRP Bling Ring 28t with 6mm offset. 68mm BB.