QP3 Wheel/Tire advice sought

Its getting time to replace the tires on my QP3...I'm looking for some advice
First... what standard tires 225/70-15 do people favor for this? I'm in Florida so no ice or snow but plenty of wet roads.
Second.. are there any alternative sizes that might work? The choices for the 225/7o originals seems rather limited...especially as I am seeking tires to improve handling.
Third//I might entertain the notion of aftermarket wheels... any thoughts/suggestions?
Steve

 

Avon Turbosteel seem to be favored by many as both quieter and with better grip than the Michelen XWXs.

I was considering new tires myself last year, but was told they weren't needed. Many miles left on mine.

All the other options I found through web searches seem to not exist anymore. There was one by Pirelli, Firestone had the Firehawk PV41 used on many police cruisers, Goodyear had the Eagle RS-A that is V rated. Michelen still makes the XWX, but they're pricey and noisy.

The Crown Victoria police cruiser in use in the USA up through the late 90's used the same size tire, unfortunately it's just long enough ago that they aren't in use anymore, and stock seems to have dried up. At least from what I was able to tell after pretty exhaustive searching last year.

There's a thread about this in the Technical Q&A forum under "Vintage tires" that goes into more depth.

Let us know what you end up with.

 

Vintage Tyres | Buy Vintage Tyres Online - FAST DELIVERY WORLDWIDE
"225/70VR15 Michelin XWX

225/70VR15 Michelin XWX Vintage tyres
225/70VR15 Michelin XWX is an unusual tyre size. There are few cars that fitted this tyre; the rear of Ferrari 512, Berlinetta Boxer (BB) and some Ferrari Daytona have wider 9" rims to fit this tyre. Though the recommended rim size for these tyres is between 6" and 8" the Ferrari 512 BB left the factory with these tyres fitted.

The Aston Martin V8 fitted the size 225/70R15. The Michelin XWX is presently the only tyre with a W (170mph) speed rating in this size and would be the best tyre you could fit."

225/70VR15 Michelin XWX
Diameter(mm) 697
Section Width(mm) 228

They list 2 tyres for this size I think. There are other sellers but really the same availability.
My 81 had on it the next size down (I can't check exactly as it is away) and it did look perhaps a bit lower and wider and seemed to run fine.

As to changing wheels any i have seen look awful. I was tempted at some point to do what I have seen done on some period Jaguars. Keep the look the same but have a wider wheel cut and shorten the half shafts etc. However, I have never looked at whether this is even possible and what the advantages may be. Also, the system seems to be balanced so would a wider tyre put undue strain on the half shaft rubbers, or rear hubs. See hub photo as there may be a couple of inches there before upsetting the sprag bars and the spring mounts but it would be an engineering and geometry challenge.

I think, all in all, that the wheels were appropriate for the car and looked good. personally I liked the XWX balloon tyre look as seen on many Ferraris of the period.
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If you're looking for a more modern daily-driver set, here's one possibility that has a resemblance to the original style --

<http://www.comp.co.uk/wheels/wheels.asp?section=th-32-13> See the TH1781 at the bottom of the page. The original 15x7.5" wheel has a 40mm offset and 5x4.5" (114.3mm) bolt circle. The center bore seems to be 62mm. All of these are within the ranges available for this 17x8" wheel. I once put an Infiniti 19x8.5, 35mm offset wheel with 245 tire on my QP3 just to see if it would fit. It does, with plenty of clearance. (Looks ridiculous, though).

235/55-17 tires have a diameter within 6mm of the original 225/70-15 and Tire Rack lists 43 types with a V speed rating or higher, 40 if you don't count winter tires.

If you can live with a tire that's smaller in diameter than the original but has a wider tread, there's the W rated Pirelli P600, available in just one size - 235/60-15. I have those on my Bora now, but I've driven it so little I can't really comment on the performance.

My QP3 is sidelined until I get some other projects done, but I will have to face this eventually. The tires on it now are too old to use.

 

Group 4 Wheels - Reviving historic rally, road and track motorsport wheels

What about this one. I am sure if I gave a wheel builder an original wheel they could make a wider rear for it? Or make a copy in the right sizes. I do like the look of the original. Here is one above that is interesting.

 

I like this company's products and their introduction says all the right things:

"Fashion has dictated that larger diameter wheels have become the norm and tyre manufacturers have stopped making for example wide 15" tyres, a problem for many performance cars from the 70's and 80's, this problem can be solved by manufacturing the same wheel but in a larger diameter where tyres are more plentiful."

Perfect! They understand the problem - so why did they make the PAG series only in 15" diameter?

However, if you could convince them to design a special 17" wheel for Maseratis, with a little care in the mold and post machining they could probably cover Bora, Merak (two types), Kyalami and QP3 with a single basic design in two widths (say, 8" and 9 or 9.5") They are apparently willing to make 17" wheels for a single Ferrari model of which only 2300 were produced, so surely the combined numbers above (>4600) would be interesting to them.

They use Compomotive for manufacturing. I have a set of GTA replica wheels from Compomotive (via Alfaholics) on my GTV. They're really high quality and certified for road use in Europe. <team3wheels.com>, <evodwheels.com> and others can also make custom wheels but they wouldn't be certified.

Hope someone pushes them!

 

Would you do the 17" for this….

 

bought 18X8 Infiniti wheels, $200 each and Bridgestone Potenza 5 for $712. problem solved.

 

HI send us some photos

 

I would. There are a lot of tire types available in that diameter. There are quite a few 18" types, too. I'd like to see Mitchell's pictures to see how it looks on the car. I "posed" an 18" wheel on my Bora. The style wasn't ideal, but even so, the rim size was beginning to look a little overpowering.

I sent a note to Compomotive to ask about their terms for partnering on a wheel design. They make replica wheels for at least a dozen companies besides Group4, so it must not be prohibitively costly. We have the 3D laser scanner and CAD software to capture the current design and stretch it to 17", then render the several versions. It will be interesting to see what they say. 4600+ Maseratis were built with variants of this design, so it should be a relatively large market for them. HBC already makes a Compomotive-built replacement for the late Ghibli, Mexico, and Indy wheel, but it's 15 x 7.5.

 

Would that work for front and back? Or would the front be 17" but a narrower tyre. The reason I ask is that years ago I put a wider front tyre on an older car and it overpowered the power steering. Rears should be fine as long as they fit on the QPIII body wise etc as you don't want it rubbing etc

 

Someone, I don't remember who was it you?, already did a stretch design of the original wheels and it was pretty good looking. I think there was an issue with which diameter looked OK. I think 18" might be a bridge too far.

 

Here is the schematic from the owner's manual. I am sure looking at this that it was envisaged that the car would have a much wider rear tyre set. Look at this and see what you think but it is an original and much better look that the same narrower tyres all round
View attachment Owner's Manual Schematic QP III.pdf

 

I ran 235/60F and 245 or 255/60R on the Bora and the rim width was the same.

 

I think 17" with a similar design to the original wheel would be perfect.
On the Merak I have been considering a set of BBS RS wheels, which looks rather good on the Merak I think.

Getting good tires in 15" is not easy anymore, and the XVX's are not my cup of tea.
Way too expensive, though they look good on the car.
Tire technology have come a long way since then, I refuse to belive that a pattern no one would even consider using today is better than the patterns today, which are made on the basis of top notch research.

 

Yes, I put up this photoshop -

http://www.ferrarichat.com/forum/142560152-post274.html

A real design would have a smaller center section compared to the rim size.

The artist who drew the QP3 cutaway might have been a little optimistic - I had mine on a lift recently and it didn't look like you could fit a tire the size shown in the drawing. I should have attempted to measure the wheelwell width. Unlike the Bora, the QP3 uses such a common bolt pattern that it should be possible to actually try various options. I think if you can keep the offset and rolling radius very close to the original you won't have steering or suspension geometry changes. The steering rack, though, is the same ZF 7842 series used in a couple of BMW 3-series cars. Seems a little small for these 4000lb beasties.

 

photos, will post photos tomorrow

 

Looking forward to it, Mitchell!

 

Hi Do you think this would be the seal kit set for this rack?
BMW 3 series, E21 replacement steering rack seal kit. 1975-84

V.M.No. 32131119224

O.E. No. 7842955112

Rack type: ZF

O.E. Seal Kit 7842 633 002

Quality Steering Seals, Kits and Boots Seal kit for BMW 3 Series Jay Gee Power Steering

 

It seems likely that the seals will work. Of course ZF could assign numbers at random, but the manuals I've found indicate that the first four digits are the major type. The QP3 unit is 7842-955-107. The BMW racks are -109 and -112. I ordered a set and will find out, thanks!

 

Let me know. I need to do the rack on my US QP III at some point.

 

Hello William / GLB...

We are all interested if the BMW steering rack kit can be used on the QPIII.. Please
post your findings here!!!

Thanks in advance...

Mike

 

It might be a couple of weeks for me, but I will take some pictures if it works out -- or maybe more importantly, if it doesn't!

 

MIE has exchange units for $500

 

Lexus, 18X8
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