Wheels again - Compomotive's

[C&C]

I know the actual answer to this is probably buried somewhere in the depths of the forum, but I have searched and not managed to turn up a definitive answer. Answer also not on Nobleparts....

I'm seriously thinking about replacing the wheels on the M400 - might as well do it now as thinking of doing the 'Ring this year and it needs a fresh set of tyres as well, so:

1. I'm looking at Compomotives - mainly due to reasonable cost and a reputation for being well built. Some of the "nicer" Trafficstar, Dymags (generally £500 - £1000 per corner plus) wheels look great but are way over budget. Any suggestions on alternatives to the Compomotives - probably go for the MO 6 spoke ones, as they appear to be the only model they make of appropriate size.

2. Talking of size - what size should be ordered? Looking at their website, there's a Noble on there which apparently has MO1810 (10 inch) rears and MO1890 (9 inch) fronts.

Looking at the US build manual, it implies the original sizes are 10 inch rear and 8.5 inch front. Quote below:

Build Manual said:

Wheels: Noble designed one piece with polished rims
Bolt pattern 4.25” or 108 mm, four hole - Centre hole 2 ½”
Front 8.5Jx18” Back spacing 5 ½”
Rear 10JX 18” Back spacing 6 ¾”

So, as Compomotive also appear to do a 8.5 inch wheel, would this be better than 9 inches?

I am assuming/hoping to stick with original tyre sizes:
225/40/18 front and 265/35/18 rear using Toyo R888 (again).

3. I haven't a clue what the offset numbers mean - the build manual refers to "back spacing" in inches, the Compomotive website refers to "Offsets Available: et1>17, et17>27 & et28>47" What does it all mean??

Any help/advice very gratefully received!

Cheers,

Conrad.

[daddysumo]

Conrad

Find the theoretical mid distance / centre line of the rim, (ie half way between the inner rim faces so on the rear 5 inches) then measure from there to the face that bolts up to the hub, that's the inset or offset and basically it positions how far the rim sits in or out to the hub.
So... get the offset wrong and the tyre could rub on the inner arch or the shock/wishbone.
HTH

Steve

Edited by daddysumo on Wednesday 3rd February 18:41

[paulcundy]

daddysumo said:

Conrad

So... get the offset wrong and the tyre could rub on the arch or the shock.
HTH

Steve

or the wheel won't clear teh caliper and you won't be able to even bolt it on.

http://paulcundy.smugmug.com/gallery/359222#162517...
http://paulcundy.smugmug.com/gallery/359222#162517...


Regards
Paul C

[F.C.]

[quote=C&C]I know the actual answer to this is probably buried somewhere in the depths of the forum, but I have searched and not managed to turn up a definitive answer. Answer also not on Nobleparts....

I'm seriously thinking about replacing the wheels on the M400 - might as well do it now as thinking of doing the 'Ring this year and it needs a fresh set of tyres as well, so:

1. I'm looking at Compomotives - mainly due to reasonable cost and a reputation for being well built. Some of the "nicer" Trafficstar, Dymags (generally £500 - £1000 per corner plus) wheels look great but are way over budget. Any suggestions on alternatives to the Compomotives - probably go for the MO 6 spoke ones, as they appear to be the only model they make of appropriate size.

2. Talking of size - what size should be ordered? Looking at their website, there's a Noble on there which apparently has MO1810 (10 inch) rears and MO1890 (9 inch) fronts.

Looking at the US build manual, it implies the original sizes are 10 inch rear and 8.5 inch front. Quote below:

Build Manual said:

Wheels: Noble designed one piece with polished rims
Bolt pattern 4.25” or 108 mm, four hole - Centre hole 2 ½”
Front 8.5Jx18” Back spacing 5 ½”
Rear 10JX 18” Back spacing 6 ¾”

So, as Compomotive also appear to do a 8.5 inch wheel, would this be better than 9 inches?

I am assuming/hoping to stick with original tyre sizes:
225/40/18 front and 265/35/18 rear using Toyo R888 (again).

3. I haven't a clue what the offset numbers mean - the build manual refers to "back spacing" in inches, the Compomotive website refers to "Offsets Available: et1>17, et17>27 & et28>47" What does it all mean??

Any help/advice very gratefully received!

Cheers,

Conrad.

Conrad,
The rim width quoted by Dymag for my car was 10" rear 9" Front, my car didn't suffer any ill effects.
The calipers were close but I've seen closer.
I think my front tyres were 235's but only because Corsa's were in short supply.
again there was no obvious problem with this.
F.C.

[Gadgeroonie]

get them ordered from reyland

http://www.reyland.co.uk/contact.asp

the wider front rims may catch on the clam on full lock but probably look a bit nicer (i went for the slightly narrower version

here are mine - i love them !

[Jim O.]

Conrad said:

Looking at the US build manual, it implies the original sizes are 10 inch rear and 8.5 inch front. Quote below:

Build Manual said:

Wheels: Noble designed one piece with polished rims
Bolt pattern 4.25” or 108 mm, four hole - Centre hole 2 ½”
Front 8.5Jx18” Back spacing 5 ½”
Rear 10JX 18” Back spacing 6 ¾”

3. I haven't a clue what the offset numbers mean - the build manual refers to "back spacing" in inches, the Compomotive website refers to "Offsets Available: et1>17, et17>27 & et28>47" What does it all mean??

What Daddysumo said. Since pictures are supposed to be worth a thousand words, here are a few that may make it clearer. First, here's a good graphic of "offset":



And here's one that includes backspace (identified as "rear spacing" on this graphic):



Note that the rim width is measured from the inboard bead seat to the outboard bead seat, while backspace is measured from the inboard flange to the mounting pad. Which means that you can't convert from backspace to offset by subtracting half the rim width from the backspace - you really have to measure the flange-to-flange distance, divide that by 2 to find the wheel centerline, and subtract that from the backspace to get your offset.

But the easiest way is to take a good look all the way around the wheel, to see if there are any size markings. Many rims are stamped with the width, diameter, and an "ET" number which is the offset...

[C&C]

Thanks everyone for the help - think I'll probably be ok with all this - just need to get measuring!

Thanks also for the tip re Reyland - it appears that as well as doing good prices on the wheels, they also supply the R888 tyres at reasonable prices too.

Cheers,

Conrad.

[daddysumo]

[quote=C&C]Thanks everyone for the help - think I'll probably be ok with all this - just need to get measuring!

Thanks also for the tip re Reyland - it appears that as well as doing good prices on the wheels, they also supply the R888 tyres at reasonable prices too.

Cheers,

Conrad.[/quote]

Phone Camskill for R888's they are usually hard to beat.

Steve

[C&C]

daddysumo said:

Phone Camskill for R888's they are usually hard to beat.

Steve

Thanks Steve - I certainly will, although last time I bought R888s I phoned them, but Steve at Simply Tyres did a better price.
I recently contacted him for a quote and he's changed business but recommended a guy called Steven Doherty via track-club.com. Phone no. 01480 411000.

So I'll be phoning Camskill, Track-club, and Reyland.
I'll let you know how I get on.....

Cheers,

Conrad.

[daddysumo]

[quote=C&C]

daddysumo said:

Phone Camskill for R888's they are usually hard to beat.

Steve

Thanks Steve - I certainly will, although last time I bought R888s I phoned them, but Steve at Simply Tyres did a better price.
I recently contacted him for a quote and he's changed business but recommended a guy called Steven Doherty via track-club.com. Phone no. 01480 411000.

So I'll be phoning Camskill, Track-club, and Reyland.
I'll let you know how I get on.....

Cheers,

Conrad.[/quote]

Any update as I need to order a set this week ??

[C&C]

daddysumo said:

Any update as I need to order a set this week ??

Hi Steve,
Sorry - no update as I have yet to sort this out.
Not likely to happen for a week or two still...
Cheers,

Conrad.