BMX cranks for DJ?

PB Forum :: Dirt Jumping & Street
BMX cranks for DJ?
  • Previous Page
Author Message
flag Wrencher
Posted: Dec 19, 2010 at 18:07 Quote
I have a few sets of BMX cranks laying around from my old days racing, but I want to convert them to fit my new MTB frame (68mm BB) can it be done? What size bearings (I heard euro, but I don't know, I do Road bikes and Downhill bikes at my shop) Where can I find em? (Jenson was my first thought) good idea? ? I want to run a 28 tooth in front, possibly a 30, but I want to know if it is possible before I spend the $. Can I run a1X9 with this?
flag jakkaroo
Posted: Dec 19, 2010 at 20:04 Quote
for bmx cranks it will variy by the cranks there are 2 sizes 19mm and 22mm euro can come in 19mm i think 22mm is mostly mid bb size if that helps at all
flag connen31
Posted: Dec 19, 2010 at 20:56 Quote
yes, 1x9 will work fine, though you wont be able to run a bmx sprocket, therefore a spider and mtb is needed.

what are the old cranks? for sealed or unsealed bearings?
yes euro is what you need
flag Wrencher
Posted: Dec 19, 2010 at 21:28 Quote
There just standard BMX cranks- like these- http://www.jensonusa.com/store/product/BB308H00-Profile+Racing+Bmx+Crank+Set.aspx
flag tcr1
Posted: Dec 22, 2010 at 18:26 Quote
connen31 wrote:
yes, 1x9 will work fine, though you wont be able to run a bmx sprocket, therefore a spider and mtb is needed.

what are the old cranks? for sealed or unsealed bearings?
yes euro is what you need

Why can't you run a chainwheel? You don't need to ru nan exterior bash and the boomerang/guide would either be mounted in the BB cup or to the ISCG tabs. What am I missing?
flag connen31
Posted: Dec 23, 2010 at 0:11 Quote
bmx sprocket/chains are a different width to normal mtbs chain. ergo if you run a bmx chain it doesnt fit through the derailer.
flag dkfreak
Posted: Dec 23, 2010 at 9:04 Quote
All kinds of em here http://www.chainreactioncycles.com/Categories.aspx?CategoryID=1909
flag tcr1
Posted: Dec 23, 2010 at 12:44 Quote
connen31 wrote:
bmx sprocket/chains are a different width to normal mtbs chain. ergo if you run a bmx chain it doesnt fit through the derailer.

Good call. Didn't think of the width difference.
flag hampsteadbandit
Posted: Dec 23, 2010 at 13:30 Quote
generally you will need to run a longer crank axle to compensate for the wider bottom bracket shell and wider rear dropout spacing (= wider chainline) on a MTB compared to a BMX

personally? I would not bother

the BMX crank with 19mm or 22mm axle on the small diameter Mountain Bike bottom bracket shell (Euro) = limited bearing durability as there simply isn't enough space in the small shell for the big bmx axle and thick bearings

some seasons back, BMX companies tried Euro shells on their street, dirt and skatepark frames and within 1 season switched to Spanish and Mid-Size press-fit shells to improve bearing durability


for a Euro shell, I'd always look at running modern Mountain Bike cranks with external bearings like Shimano SLX HT2 or Saint HT2 with a 32T chainring and then set the size of the rear cog to suit the front chainring Wink


you can see a SLX HT2 setup with Middleburn 36T DH chainring and E13 LG1 chain device on this Wildcard we just built for a customer

photo


perhaps EBAY the Bmx cranks to help fund the purchase of new cranks!
flag sammysmc
O+
Posted: Dec 23, 2010 at 16:06 Quote
You need a longer spindle. to run 1x9 you'd need get a 3/32 sprocket and a chain guide that will work with bmx cranks
flag stevehollx
Posted: Dec 29, 2010 at 9:59 Quote
Profile has 19mm cranks that will fit in their euro BB. They also make a sprocket for 19mm (imperial) which will fit a 9-speed chain.
flag hampsteadbandit
Posted: Dec 29, 2010 at 11:53 Quote
Profile has 19mm cranks that will fit in their euro BB.

they certainly do, but also offer a range of axle lengths so purchase the right one, carefully Wink
flag ryann-93
Posted: Feb 8, 2011 at 14:50 Quote
hampsteadbandit wrote:
Profile has 19mm cranks that will fit in their euro BB.

they certainly do, but also offer a range of axle lengths so purchase the right one, carefully Wink
I know it's late but if your still buying some make sure you check the angle of the Crank arms (crank arms bend out slightly, I only have just over 1mm gap between my crank arm and chainstay, luckily it doesn't rub (Y)
flag jakkaroo
Posted: Feb 8, 2011 at 14:54 Quote
JustRyann wrote:
hampsteadbandit wrote:
Profile has 19mm cranks that will fit in their euro BB.

they certainly do, but also offer a range of axle lengths so purchase the right one, carefully Wink
I know it's late but if your still buying some make sure you check the angle of the Crank arms (crank arms bend out slightly, I only have just over 1mm gap between my crank arm and chainstay, luckily it doesn't rub (Y)
theres these cool little things called spacers you should try some
  • Previous Page

 


Copyright © 2000 - 2024. Pinkbike.com. All rights reserved.
dv42 0.016167
Mobile Version of Website