number-1
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| posted on 18/11/12 at 03:46 PM |
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RWB BEC drive chain?
Does anyone know where to get a drive chain for a RWD BEC? Any common sizes?
Cheers
N1
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Andy B
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| posted on 18/11/12 at 04:28 PM |
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It really depends on what front and rear sprockets you are using. Personally I would only use 530 chain and have found that the DID x-ring is one of
the best on the market, we use it on our Sabre racecars and have never had one let go and I also used them on 190bhp F1 sidecars with no issues. You
just need to know what length you need in links, we keep them on the shelf for sabre and obviously you can cut them down but you will need a splitting
and riveting tool - definately no spring clips for this one!
regards
Andy
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minitici
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| posted on 18/11/12 at 04:34 PM |
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I usually recommend DID530ZVM-X chains for mid-engined BECs.
This is what we use on the ZX14 powered Radical Clubsport hillclimb and sprint car.
You still need to be a bit careful with your driving style - try not to set off with any slack in the chain and don't do on-off tyre warming.
The Radical usually gets a full season out of a chain (about 30 events) with many standing starts.
I presume you are using 530 type sprockets?
I saw from your other post that you had chain problems at your test.
Were the chain and sprockets new?
If so what size/type were they.
New chains can stretch slightly but after their initial bedding in they should not change their tension from run to run.
I have seen several cars where the owner was having to adjust the chain tension every run - invariably this is due to the differential, engine or
chassis deforming under load - so make sure that all your mounts are strong enough.
How long is your chain run?
With a BEC chain drive you can run the slack a bit less than recommended for a bike as the chain angles do not vary with the wheel movement.
Doug
[Edited on 18/11/12 by minitici]
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number-1
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| posted on 18/11/12 at 05:23 PM |
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Cheers for the replies chaps
The car has very little history with it so ive had to hunt around for exactly what its got, hence not knowing too much about it. I know it was used
for sprints and hill climbs...so quiet a bit static fast pull offs
The chain/sprockets were with the car already fitted....Im presuming they are old and used although they dont look worn. There is loads of slack. The
options are either get a new one, or use shims to increase the distance between front sprocket and the rear diff by pusing it back by x amount until
the correct tension is found
The length is unknown but ill try and find out. Same with the sprocket make and type
Heres a pic of the rear....its had a shim used already by the looks of it?
[img]http:// [/img]
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maccmike
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| posted on 18/11/12 at 06:06 PM |
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Hows ya car coming along?
quote:
Originally posted by number-1
Cheers for the replies chaps
The car has very little history with it so ive had to hunt around for exactly what its got, hence not knowing too much about it. I know it was used
for sprints and hill climbs...so quiet a bit static fast pull offs
The chain/sprockets were with the car already fitted....Im presuming they are old and used although they dont look worn. There is loads of slack. The
options are either get a new one, or use shims to increase the distance between front sprocket and the rear diff by pusing it back by x amount until
the correct tension is found
The length is unknown but ill try and find out. Same with the sprocket make and type
Heres a pic of the rear....its had a shim used already by the looks of it?
[img]http://[/img]
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minitici
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| posted on 18/11/12 at 07:28 PM |
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Thanks for the picture of your chain drive.
Looks like a Quaife QDF7ZR sealed chain drive differential.
To tension your chain you would need to shim the mountings - a bit of a pain to do.
Alternatively you could install some form of pivot carrier or an eccentric mount to tension the chain.
I've made a few over the years if you need any tips.
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number-1
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| posted on 19/11/12 at 08:26 PM |
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Hmmmm...what did you have in mind for the pivot? Any pics? And would shims not be easier adding 1mm at a time until its the right tension?
[Edited on 19/11/12 by number-1]
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minitici
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| posted on 23/11/12 at 12:18 PM |
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Shims can be a real pain to try and insert once the chain gets near the correct tension.
Thin shims tend to buckle as you fit them.
Usually involves levers and skinned knuckles....
 
pivot carrier 2
This is a typical pivot carrier (was fitted to a couple of R1ots)
The carrier pivoted on one of the bottom mounts, the other bottom mount was bolted to a quadrant for extra support and the top mount was bolted to the
chassis via turn-buckles to aid chain tensioning.
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