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Bimota Composite Wheel Help

 
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PaulDB2



Joined: 26 Apr 2014
Posts: 316
Location: Manchester

PostPosted: Thu Feb 23, 2017 2:21 pm    Post subject: Bimota Composite Wheel Help Reply with quote

Preparing for the show I have finally got around to the back wheel of my DB1 which has had a serious air leak from part of the split rim ever since I bought it. I had asked the seller to run some super sticky silicone around the join when he put new tyres on before shipping it to me. When it wouldn't hold air I assumed/hoped he hadn't done it. Behold the picture when I had the tyre removed this morning.
[img]

There is a thin layer of what appears to be evostick which can be pulled off but underneath that there is a broad band of what appears to be some resin impregnated tape in the well of the rim.
Is this how they came from the factory? (Seems pretty crude, especially from Bimota) Or has someone had a drastic go at fixing this issue previously?
Anyone seen these 16 inch composite rims bare?
Had hoped I could run a bead of Sikaflex around the rim joint but to cover this lot would take tubes of it.
The other alternative was to stick an inner tube in it, but the tyre guy was unhappy to do that because of the offset valve and that the tube was likely to be too large for the 160/60 profile.
Might be at the show with a flat tyre but I want this bike to be rideable so any help/advice considered. Thanks [/img]
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Jonny B Bad



Joined: 05 Dec 2009
Posts: 554
Location: NE London

PostPosted: Thu Feb 23, 2017 4:15 pm    Post subject: DB1 wheel Reply with quote

Have you tested the integrity of the bead area by spraying liquid on to it with the tyre mounted and with pressure?
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2bims



Joined: 03 Apr 2010
Posts: 7289

PostPosted: Thu Feb 23, 2017 4:26 pm    Post subject: Reply with quote

Theres a guy coming to the Show...that comes every year...that used to own my DB1....admittedly if I ask him at the show...that's a bit late...so I'll give him a bell and find out...as he still has his Old DB1 wheels, with presumably no tyres on...he will at least be able to look/see....Defo looks "aftermarket" to say the least...I'd still say a tube is best...at least for the show...which...aint that far away.....
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PaulDB2



Joined: 26 Apr 2014
Posts: 316
Location: Manchester

PostPosted: Thu Feb 23, 2017 7:31 pm    Post subject: Re: DB1 wheel Reply with quote

Jonny B Bad wrote:
Have you tested the integrity of the bead area by spraying liquid on to it with the tyre mounted and with pressure?

Hi Jonny, thanks but it is definitely the split rim, have had it in water to check.
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PaulDB2



Joined: 26 Apr 2014
Posts: 316
Location: Manchester

PostPosted: Thu Feb 23, 2017 7:32 pm    Post subject: Reply with quote

2bims wrote:
Theres a guy coming to the Show...that comes every year...that used to own my DB1....admittedly if I ask him at the show...that's a bit late...so I'll give him a bell and find out...as he still has his Old DB1 wheels, with presumably no tyres on...he will at least be able to look/see....Defo looks "aftermarket" to say the least...I'd still say a tube is best...at least for the show...which...aint that far away.....

Cheers Steve and thanks for the call.
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Mike Jennings



Joined: 22 Mar 2008
Posts: 286
Location: England

PostPosted: Sun Feb 26, 2017 4:18 pm    Post subject: Reply with quote

Hello,

do you mean the thick solid layer of resin that extends around the inside of the rim to seal the joint between the two halves of the wheel? If so, that's how they come from the factory, at least the wheels I've had all had that sealant,

Cheers, MikeJ
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PaulDB2



Joined: 26 Apr 2014
Posts: 316
Location: Manchester

PostPosted: Sun Feb 26, 2017 5:10 pm    Post subject: Reply with quote

Hi Mike, so that broad band of resin across the well of the rim (about 2.5 inches wide) is factory original?
I am used to built up race car rims where just a layer of sealant on the rim faces where they bolt together is sufficient.
I have found an area in the resin that seems to have been gouged a little, wondering if that is sufficient to cause the leak.
Thanks for the info Mike.
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Mike Jennings



Joined: 22 Mar 2008
Posts: 286
Location: England

PostPosted: Sun Feb 26, 2017 5:32 pm    Post subject: Reply with quote

Hello Paul,

yes, my wheels have that broad band of resin too, I'd guess it's some form of aircraft adhesive,

Cheers, MikeJ
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2bims



Joined: 03 Apr 2010
Posts: 7289

PostPosted: Sun Feb 26, 2017 6:15 pm    Post subject: Reply with quote

Would you consider Tubing the tyre Mike? even though the outlet for the valve is slightly offset from the centreline due to the composite halves being dead centre?......I have a leaky front but rear is solid....Mine at least holds air for a few weeks....even if ridden...I think Pauls goes flat in under a day so more of a concern....
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Bud977



Joined: 03 Mar 2013
Posts: 525
Location: Sydney

PostPosted: Sun Feb 26, 2017 8:17 pm    Post subject: Reply with quote

I've got Astralite wheels on one of my TZs and they just have a small bead of silicon at the centreline to seal the halves. Apparently Astralites aren't meant to run tubeless, but I do as I'm not keen on the offset valve if you fit a tube, same as if you fitted a tube to your wheel.

It would be best to paint over the resin with some sort of rubberised sealant. Don't know what though. Or chip it out and put in the light bead of silicon. The rim shouldn't be porous anywhere else.
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Mike Jennings



Joined: 22 Mar 2008
Posts: 286
Location: England

PostPosted: Sun Feb 26, 2017 10:25 pm    Post subject: Reply with quote

Hello Steve,

I had tubeless tyres fitted to my DB1 and they're still holding air, so I've not had to fit tubes. It would probably be best to ask a tyre specialist about using a tube with the offset valve hole as I've not tried it myself. Given the thickness of the resin seal, it might be that it's a bit structural and perhaps prevents the two wheel halves 'working' w.r.t. each other?

Cheers, MikeJ
P.S. If the leak is at one particular place and the resin is permanent, maybe epoxy resin would do the job?
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welshlamb



Joined: 09 Mar 2011
Posts: 592
Location: South Wales , Nr. Abergavenny

PostPosted: Sun Feb 26, 2017 11:17 pm    Post subject: Reply with quote

leaking air is only one issue for running tubeless.

Don't wheels designed for tubeless tyres have a different beading arrangement so that tyre doesn't come off the rim in case of sudden deflation ?
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Mike Jennings



Joined: 22 Mar 2008
Posts: 286
Location: England

PostPosted: Mon Feb 27, 2017 3:40 pm    Post subject: Reply with quote

Hello Welshlamb,

this is more about fitting a tube inside a tubeless tyre, so the bead would still be suitable for a tubeless rim,

Cheers, MikeJ
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