Cranks rubs on BB?

OllieTheWelder

Hi, I bought a DMR Trailstar of my mate yesterday on the basis that the BB was crunchy. He said it would need a new BB but after dismantling it it looks fine. I think the problem is that the crank is to close to the BB and when the bolt is done up it pulls the crank into the bottom bracket causing it to be tight and crunch. Would I need some spacers to keep the crank away from the bottom bracket? It has one spacer but it seems useless and I think more are needed but I'm not 100% sure?

I'll add pictures tomorrow.

Thanks, Ollie.

supersonic

What crank and bottom bracket?

cooldad

What is the BB, what are the cranks.

Edit. Never mind

OllieTheWelder

I'm not sure what the bottom bracket is. Here's some pics though. The cranks are Kona and are splined.





Ollie

OllieTheWelder

Also the end of the crank arm on the pedal side sometimes hits the frame?

styxd

You need some spacers in there, the crank is nearly touching the frame!

1mancity2

Looks like wrong size bb to me, and the crank looks like a 3 piece bmx crank.

benpinnick

Yep, 73mm BB in a 68mm housing. The threaded part should not be visible.

OllieTheWelder

Aww more money to spend... The threaded part shown will screw fully into the frame however this means that the crank hits the frame? Could someone give me a link to the correct things i need please?

1mancity2

first off measure the tube were the bb is will be 68mm or 73mm (68mm like my sidekick2)

OllieTheWelder

It's 68mm.

1mancity2

put a pic up of the crank arms so we can see the fitting type.

OllieTheWelder

Not sure what you mean? There is already a picture of the crank arm?

The Rookie

Clearly BMX 'style' crank arms and BB but a 73mm BB in a 68mm shell and not wide enough to fit round an MTB frame, just needs to go and source the right BB/crank combo to suite!

I am about to remove a Gusset crank/BB set up from a Scott Voltage that would suite just fine!

Simon

OllieTheWelder

I don't think the BB is wrong. It will screw all the way in however I have left it part way out otherwise the cranks will hit the frame when it is rotated. I think if I got some spacers that fitted inside the BB on the axle inbetween the BB and the cranks, this would both stop the cranks and the BB rubbing and the crank arms hitting the frame. I didn't realise they were BMX cranks. Do Kona maka BMX cranks, I thought they only did MTB?

cooldad

Whatever you do to the BB, the axle length is still wrong. Presumably the cranks are not fitted to the splines properly at this point?

OllieTheWelder

Cranks fit the axle fine. It could be that the axle is too short though?

1mancity2

OllieTheWelder wrote:

Cranks fit the axle fine. It could be that the axle is too short though?

can you take a pic of the bb out of the bike?

may be a sticker on it saying what it is and size, I have a 68mm bb and rpm chainset of my dmr sidekick2 some were.

nicklouse

Change the centre spacer to a 68mm one and add some spacers to the arm side.

Tht is one I the worst 3 piece crank setup ever.

OllieTheWelder

Haha I always get the phucked up ones . Anyways pictures as asked may help some of you?






(Fully screwed in)



Ollie.