Welcome to our Site for MG, Triumph and Austin-Healey Car Information.
MG MGB GT V8 Factory Originals Technical - How Much Power Can Be Used With Wire Wheels?
|OK, Horsepower Fans-|
I'm presently trying to decide which size wheels to use on my V8 project car. I love the classic looks of chrome wire wheels, but am unsure as to just how much horsepower they can absorb and still be reliable. This, of course, has a direct influence on which size and state of tune I'll choose for the Rover engine. Right now I'm leaning toward 72-spoke 15" wheels.
To be safe I suggest you discuss with the Vendor of the wheels you intend to fit - then if you have lots of spokes work loose or break you may have some recourse.
In practice I believe that stainless or painted spokes will be stronger than chrome spokes of the same dimensions - again your supplier should be able to advise you.
Consider using bolt-on wire wheels. Your splined hubs will have a hell of a time coping with the V8's torque, and I'm afraid it will be a losing battle.
|Unfortunately, vendors are in the business of selling, not handing out engineering specs. Since this part of the BBS deals with V8 conversions, I hoped that there might be someone out there with first-hand experience who could advise me on just what the power limitations of wire wheels are. I know that Aston Martin stopped using wire wheels when the output of their engines reached 250 HP due to repeated customer complaints about broken spokes, but that was a heavier car.|
you need to look out for a posting from Roger Parker when he comes on line-I know that his original FI conversion used wire wheels- with 72 spokes- I believe and in excess of 190bhp at the rear wheels. He has now changed to knock on minilites.This question has come up before and his replies have indicated that even the strongest wires are no match for a well tuned V8 and tyres able to hook up the power to the road.
|Hi John et all,|
Yes been away this week so a little later here than normal.
As John says my car, a 1968 roadster, was originally fitted with wires and prior to going V8 in the early 1980's I had already sourced some OE Dunlop manufactured 5.5"x14 72 spoke wires. Previously with a reasonably warm 1950 4 cyl engine I had a series of loosening front spokes on brand new Dunlop standard painted wires, two sets of which I collected from the factory and these had been through an extra checking procedure because I had the problem, and my contact was a director of the company!!
The subsequent use of the chrome 72 spoke units solved the problem with the 4 banger and did quite alot in the looks dept. When I went V8 I retained these wheels for the asthetics although it was soon apparent that whilst the spokes were not loosening, the wheels were reacting to the torque and distorting. This was showing up with constant wheel balance issues.
This also raises the more valid point that it is the torque rather than power that is the problem, and whislt I have a very effective 3.5 litre motor the torque from a mild 3.9 or standard bigger capacity lump will far exceed that of my engine and certainly cause more serious problems.
In the early 1990's I was fortunate enough to come upon a set of mint Minilite style knock ons of 6x14 size. I have these on the car today.
Now apart from the obvious distortion of the wheel that was causing the balance problems there was a more worrying issue in my mind. This relates to the fact that a wire needs a tube (unless technology has created somehting better since!) and this wheel distortion would be loading the tube with stress that may lead to failure, especially around the poijnt where the valve node pokes through the rim.
The prospect of a 145mph car having the tube rip and deflate rapidly at speed was uncomforatable to say the least. Consequently this was the main reason for the change to a rigid rim that simply takes just a tyre and no tube. I also have the bolt in reinforced valves to add extra security.
On the subject of splines I have seen no problem in the 16 years since conversion and I would simply say that if the splines are new and or not worn then the free movement on them will not show any problem.
You've answered my questions and confirmed my suspicions that Panasports would be safer due to eliminating distortion and the chance of a ripped inner tube. It seems that the chrome wire wheels will continue to be OK for my warmed-over 1972 4-banger, but Panasports will be the way to go for my BMIHT bodyshell V8 which is in the planning stage. Thanks to all who helped.
This thread was discussed between 15/01/2001 and 21/01/2001
This thread is from the archives. Join the live MG MGB GT V8 Factory Originals Technical BBS now