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phil75
Sr. Member
Posts: 105
Matra Passion Member
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« Reply #2 on: February 09, 2008, 01:50:56 pm » |
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I have tires into 235/40R17 for the back and 215/40R17 for the front on the other hand at late I put a spacer of 10 millimetres if not the tire rubs the arm
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- Philippe - Matra Murena 2.2 1983 engine 20000 km Yamaha R1 2004 9000 km (engine) VW Golf II 1.8 1990 209000 km Rover 111 1994 155000 km
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Megatech
Jr. Member
Posts: 25
I'm a llama!
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« Reply #8 on: February 09, 2008, 08:57:07 pm » |
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You can never agree on looks and taste, and old wheels can allways be refitted - please do as you like.
However, there are some practical points to consider:
Width and offset: Standard is 195 mm and 25 mm. This mean 122,5 mm goes inside and 72,5 mm goes outside relative to connection surface on the brake disc, which is fixed. Inside is a small clearance between tire and travelling arm, so do not exceed 130 mm.
Tire profile: Standard is 60%. The suspension, damping, weight and tire profile together makes a suspention system. If you change one or more of them, they might get out of balance. This could cause poor handling. I have experienced this on a X 1/9.
Offset: Some use distance discs to compensate for 35 mm offset (FIAT) or to extend the track. If you change the offset, you put non designed stress to the bearings.
Tire sizes: You may experience, that the ideal tire set for the Murena is not available.
But most important: SAFETY FIRST 17" rims - I would imagine, does conflict with some of the above.
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Anders Dinsen
Administrator
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Posts: 3188
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« Reply #11 on: February 10, 2008, 12:00:58 am » |
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Tire profile: Standard is 60%. The suspension, damping, weight and tire profile together makes a suspention system. If you change one or more of them, they might get out of balance. This could cause poor handling. I have experienced this on a X 1/9.
I agree totally with you there. A 60-profile sidewall is quite soft and deflects quite a lot in lateral acceleration (i.e. cornering). Even the 55-profile's I run at the front are much stiffer than the standard 60's I have on the rear. This was recommended to me by Roy who experienced quite a decent handling improvement when he switched. As I haven't tried anything else, I can't compare, but I find it performs well both on my Yokohama summer tires and Pirelli winter tires. So it appears, that this particular change is within the practical range of improvements. I'd guess that the 50-profiles that a 15" rim would necessitate would also give a slight improvement in performance. If I had the money to experiment (or a tyre sponsor?) it could be interesting to do some tests with different tyre profiles and sizes. Offset: Some use distance discs to compensate for 35 mm offset (FIAT) or to extend the track. If you change the offset, you put non designed stress to the bearings.
Unfortunately AFAIK, distance rings are illegal in this country? Tire sizes: You may experience, that the ideal tire set for the Murena is not available.
What exactly do you mean? But most important: SAFETY FIRST 17" rims - I would imagine, does conflict with some of the above.
Agree
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1982 Talbot Matra Murena 2.2 prep 142 2017 BMW i3 "Charged Professional" 94Ah
Used to own: 2001 Renault Matra Grand Espace "The Race" V6 24v 1997 Renault Matra Espace 2.0 8V 1987 Renault Matra Espace J11 2.2
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