NS Dev
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 posted on 30/1/07 at 06:40 PM |
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lobro cv joint size
on my new grasser I am a bit stuck as to which cv's to use.
my old one used 100mm 25 spline cv's, but I have been advised that these will not be strong enough on the new grasser (two Aprilia RSV 1000cc
vee twins, 310hp ish)
Most of the twin bike engine grassers use 108mm CV joints and I have seen a fair few broken ones.
This lead to me thinking I needed 108 cv's
However I called my mate at ultima today to see if he had any 108mm outer stub shafts I could use to go in my sierra hubs, and he said he did by
chance, but they only use 100mm joints on the ultima, and questioned the logic of using 108mm jobbies as they put 720hp and 680lbft of engine power
though 100mm ones in a 900kg car, he reasoned 100mm ones should be plenty strong enough in a 500kg 310hp car!!!
now I don't know what to use, and changing up to 108 from 100 will mean a whole new shaft assembly if the 100mm joints don't work, if they
do, they are MUCH cheaper!!!
Any ideas, anybody know where the official GKN torque handling specs for their CV joints might be on tinternet?
Retro RWD is the way forward...........automotive fabrication, car restoration, sheetmetal work, engine conversion
retro car restoration and tuning
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andrew-theasby
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| posted on 30/1/07 at 09:58 PM |
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Cant answer your question, but maybe the grassers break the 108mm joints cause of the amount of suspension travel they have ie running at greater
angles. Ultimas presumably have hardly any movement so they probably run straight most the time?? Just an idea
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MikeR
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| posted on 30/1/07 at 10:55 PM |
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also grassers do lots of dumps of the power. I imagine ultima's do a fair few 0-60's but no where near as many as the grasser.
Have you spoken to GB engineering & seen what they think? If they're making the drive shaft they might have an idea what the joint either
end will take.
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Liam
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| posted on 31/1/07 at 06:20 PM |
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Hmmm - i'd say with low gearing, full power dumps, loads of traction, and lots of suspension travel, CVs may get more of a hammering in a
grasser.
If you've seen plenty of broken 100mms in your particular application, i'd be tempted to go for the 108s.
Also bear in mind there are probably crap 108mm CVs and decent 108mm CVs...
Liam
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NS Dev
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| posted on 1/2/07 at 08:13 AM |
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quote:
Originally posted by MikeR
also grassers do lots of dumps of the power. I imagine ultima's do a fair few 0-60's but no where near as many as the grasser.
Have you spoken to GB engineering & seen what they think? If they're making the drive shaft they might have an idea what the joint either
end will take.
Yes, but the world record ultima has done almost continuous acceleration tests for magazines and the company for the last two years on the same set of
100mm cv's, lets not forget is does 0-60 in 2.6 secs, 0-100 in 5 and weighs 900kg!!!
I think the wheel travel might be the answer.
berrisford said use 108mm
Think I probably better had. The GKN 100mm ones that Ultima use are £140 each anyway!
Retro RWD is the way forward...........automotive fabrication, car restoration, sheetmetal work, engine conversion
retro car restoration and tuning
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