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stevecollie

4Rt Rear Centre Hub

19 posts in this topic

Ok..................Call me Stupid

I've managed to elongate the holes on the hub of the back wheel

I could do without buying a new wheel at the moment

Any suggestions would be welcome

I dont think it's possible just to buy just a hub........................is it?

I was thinking about drilling it out larger and putting in a collar, is this a good idea

Thanks.......................Stupid

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Take it to a good engineer and let them see it, there's usually a fix.

If the holes are enlarged and tapped they have to retain the same/original centre, and you would have to also drill the sprocket. An engineer might be able to put inserts in, depending on how much "meat" there is.

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Used to be able to just buy the hub if all else fails - 315 mont can be used but would need different sprocket and disc.

PS What holes are you refering

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Yep :blush:

Was it caused by loose bolts?

Check price of hub from Sandifords/Pidcocks, before looking at Engineering options

I had a little job done last week and it would have been nearly as cheap to buy the new part from a dealer :wall:

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Was it caused by loose bolts?

Check price of hub from Sandifords/Pidcocks, before looking at Engineering options

I had a little job done last week and it would have been nearly as cheap to buy the new part from a dealer :wall:

1: Loose Bolts :blush:

2: Will do thanks

3: Having read the advise, I have spoken to an engineer 5 mins ago, his boss is on holiday, as luck would have it, and he say's he'd have a look, if he can fix it, he'd do it for beer money, now that's my kind of engineer

Watch this space

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How bad are the elongations. Sprocket should centalise using the centre hole of the sprocket to give alignment. Bolts just hold it in place via the clamping force generated when tightened up. The fit of the bolt in the hole on the hub is irrelevent once tightened so long as the hole has not elongated that much that there is not enough strength left. Any repair that does not involve welding and redrilling is not going to give that strength back anyway. .

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Thanks for the replys gentlemen :thumbup:

There is a fair bit of movement

I've handed it in, he's going to give it a go

He has both the wheel and sprocket

Failing a fix................... looks like that I'll have to dig deep :(

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Jimmy is quite right that the bolt is there to just to provide a clamping force and if the bolts are tightened properly then it is the friction between the sprocket and hub that stops any relative movement and not the bolts resistance to shear. Bolts for connections like this are not meant to act in shear, they act in tension. If the elongation in the hub holes is not too bad and the sprocket can be centered on the hub, then you may not have to do anything other than bolt it up to the right torque settings. Make sure the surfaces of the sprocket and hub are clean and flat first. Check the manual to see if there is a tightening sequence and torque setting for these bolts.

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Cannot use a 315 hub with a 4RT rim as mentioned above ... 315 uses 36 spokes and 4RT uses 32 spokes.

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Cannot use a 315 hub with a 4RT rim as mentioned above ... 315 uses 36 spokes and 4RT uses 32 spokes.

Too true - complete wheel is a drop in part tho after 2000 model year.

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Too true - complete wheel is a drop in part tho after 2000 model year.

True

I alternate between the original 4RT wheel and a complete 315 wheel

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Turns out you can buy the Hub Only :thumbup:

£72.00 from Pidcocks

If the repair fails, it'll be plan B then

Which incidently should have been Plan A :unsure:

Thanks again, Gents

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plus the cost of the wheel build...? unless you have a go yourself?

(wheel building skills could be handy on Rannoch Moor...)

;)

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