Which wheels

[d mulcahy]

As stated in another post I have just purchased a Roadster, the car has TR7 steel wheels and has GT6 engine and running gear I would like a nice set of alloys Im sure MGF wheels fit but these are available in different size at present its on 13" would I be better with bigger wheels or stick to 13's any advice would be helpful, cheers Dave.

[jon_cox]

Re: Which wheels

No advice I am afraid. I think it is personal preference really. However, if this helps make up your mind there are some very nice alloys on ebay at the moment. Nothing to do with me I just noticed them whilst surfing and thought of you.......

http://www.ebay.co.uk/itm/YKC-Marlin-roadster-alloy-wheels-and-tyres-/231345623494?pt=UK_CarParts_Acc_Wheels_tyres_Rims_Car_Wheels_ET&hash=item35dd4611c6

[d mulcahy]

Re: Which wheels

Thanks for the thought, the wheels are from Sierra based YKC so won't fit as the PCD is different to the Triumph think I have found a set locally will check when I collect the car on Wednesday. Thanks again Dave.

[stevejgreen]

Re: Which wheels

Whilst you can fit larger rims and lower profile tyres, I have reservations over the handling and ride issues.
Low profile tyres have a lot less sidewall deflection. This can help with more directional steering, but the trade off is in suspension harshness.
Its a matter of personal choice.
The standard Marina 13" wheels had a 1/2" offset. Fitting wheels of a different offset and tyre width may mean that spacers are required meaning that ideally the wheel studs should also be changed.
Ideally the wheels should locate on the hub, the studs should not be relied upon to centre the wheel as they are unusually small diameter.

[jon_cox]

Re: Which wheels

Thanks for the thought, the wheels are from Sierra based YKC so won't fit as the PCD is different to the Triumph think I have found a set locally will check when I collect the car on Wednesday. Thanks again Dave.

NO, these are definitely for the Marina / Triumph models. Look at the way the wheel nut holes have been drilled. They are so close to the centre that the machining has taken out a little moon shape.

[d mulcahy]

Re: Which wheels

NO, these are definitely for the Marina / Triumph models. Look at the way the wheel nut holes have been drilled. They are so close to the centre that the machining has taken out a little moon shape.

Thanks again Jon after Steve Greens reply I'm a bit confused he states that he thinks I should stick to 13" so not sure which way to jump. Anyway phoned the guy to check that there still available.

[cameronfurnival]

Re: Which wheels

the Romero (same chassis as the YKC Roadster) recommended 14" wheels and many sierras were so fitted. The answer I think lies not in what the original spec was but how you want the car to sit, look and drive - so putting 185/75/13 tyres on a 13" rim is almost identical to 185/65/14 (speedo would read 69mph instead of 70) the bigger wheel would look much better imho but the rolling radius is the same give or take. The handling would be better for the marginal reduction in sidewall too, without becoming harsh.

[stevejgreen]

Re: Which wheels

the Romero (same chassis as the YKC Roadster) recommended 14" wheels and many sierras were so fitted. The answer I think lies not in what the original spec was but how you want the car to sit, look and drive - so putting 185/75/13 tyres on a 13" rim is almost identical to 185/65/14 (speedo would read 69mph instead of 70) the bigger wheel would look much better imho but the rolling radius is the same give or take. The handling would be better for the marginal reduction in sidewall too, without becoming harsh.

Recommended wheels on a YKC Sierra based Roadster will be more to do with the necessary clearance to fit the Sierra Brakes than a particular appearance/performance upgrade.

[cameronfurnival]

Re: Which wheels

Recommended wheels on a YKC Sierra based Roadster will be more to do with the necessary clearance to fit the Sierra Brakes than a particular appearance/performance upgrade.

so 14" wheels will fit a Marina based roadster with plenty of clearance. and look a lot better (appearance) and take wider tyres (performance).

[Alan c]

Re: Which wheels

Steve Greens point on spacers that locate wheel should not be underestimated. When I bought my Marlin I had wheel shake typical of out of balance. When I took it to the tyre shop for balancing they pointed out I had generic type spacers which had no concentric spigot to locate the wheel so the balancing would not fix it. Took me a while to identify the right ones (much measuring) then when I did they were a few mil thicker so needed new studs. It did the trick though. (think it was a £60 exercise so factor in)

Alan

[stevejgreen]

Re: Which wheels

With regard to possible handling problems here ara a few thoughts.
There are two different diameters of torsion bars. The Standard for all saloons was 21h5747 at 19mm diameter, vans and HD pack were 21h5437 20.6mm diameter.
Through the years there were five different Marina damper ratings available, it is my guess that the Triumph Herald rears used by Marlin were chosen because they fitted, rather than for their specific damping qualities, though of course these can be changed to Spax adjustables.
The unladen weight on the front axle of my Roadster was around 400kg, I have no similar front/rear axle weight figures for a Marina but, the Roadster will have less body weight than a Marina and with the Roadsters engine mounted further rearward, there is even less weight on the front axle.
This means that there is a likelihood that the Roadster front suspension is already very stiff, and my supposition that a lot of the ride comfort will come from the sidewalls of the tyres deflecting, rather than the torsion bars or Herald rear dampers.

I remember that Jez Cox did some suspension calculations published either on the Forum or Pitstop.

[d mulcahy]

Re: Which wheels

With regard to possible handling problems here ara a few thoughts.
There are two different diameters of torsion bars. The Standard for all saloons was 21h5747 at 19mm diameter, vans and HD pack were 21h5437 20.6mm diameter.
Through the years there were five different Marina damper ratings available, it is my guess that the Triumph Herald rears used by Marlin were chosen because they fitted, rather than for their specific damping qualities, though of course these can be changed to Spax adjustables.
The unladen weight on the front axle of my Roadster was around 400kg, I have no similar front/rear axle weight figures for a Marina but, the Roadster will have less body weight than a Marina and with the Roadsters engine mounted further rearward, there is even less weight on the front axle.
This means that there is a likelihood that the Roadster front suspension is already very stiff, and my supposition that a lot of the ride comfort will come from the sidewalls of the tyres deflecting, rather than the torsion bars or Herald rear dampers.

I remember that Jez Cox did some suspension calculations published either on the Forum or Putstop.

Thanks for all the replies, I have spoken to the seller today and have been informed that the wheels came from a Marina based kit so pcd should be the same. My car is a" Hy-brid" with Triumph GT6 engine and front suspension and Marina rear axle would this affect the clearence for the fr. brakes. Cheers Dave.

[stevejgreen]

Re: Which wheels

There are few issues for wheels with the correct PCD on the rear of a hybrid with a Marina axle. As said previously take care of the offset and any spacers that may be used. But, the tyres must not extend beyond the bodywork and should ideally alighn with the fronts.

I can not advise on the peculiarities of a Triumph suspension though I gather there are differences depending on the original donor vehicle. Ben is your man there!

[b_caswell]

Re: Which wheels

All the Herald/Vitesse/GT6 and Spitfire cars use wheels with a half inch off set ( that is the centre line of the rim is inboard of the hub face by half an inch) regardless of the rim width 3.5 up to 5.5 inch 13 inch dia and have a 3.75in PCD........... If the YKC wheels pictured above are from a Marina/Ital kit they should be ok for the hybrid but its quite possible they are Maestro or Montego wheels that also have the same PCD but not sure of the off set. The Triumph wheels to avoid are those from the Dolomite range off cars as they have a different off set. 14 inch rims wont be a problem but I would avoid going over board on tyre width.

[jon_cox]

Re: Which wheels

These wheels are not from a Montego. Marlin originally offered an alloy wheel that we all know and love from a company called Cosmic and the wheel was the Ribster. Then when these became unavailable Marlin offered the Compomotive CX alloy wheels which YKC took over the last of the stock. When this stock ran out they chose to offer the KN Diamond alloy wheels which is what these on eBay are. If you zoom in on the picture you can see the KN logo.