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Help! 308 to 348 wheel conversion...?

Discussion in 'Technical Q&A' started by JonnyT, Jan 22, 2004.

  1. JonnyT

    JonnyT Karting

    Jan 21, 2004
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    Jean-Paul
    I figured this was actually the right place to post this...sorry. Has anyone ever put 348 wheels on a 77-79 308GTS? I have an opportunity to purchase some at a great price and I'm wondering what type of hassle I'm in for. Jonny
     
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  3. BigAl

    BigAl F1 Veteran

    Mar 17, 2002
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    I would imagine someone has. Have you searched the archives?
     
  4. snj5

    snj5 F1 World Champ

    Feb 22, 2003
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    If I remember right, the bolt pattern will fit, but the offsets are quite different and spacers would be required. May need to be careful about the rear tire size - 348s run 255 and the largest I've heard 308 folks typically run are 245/45.
    Good luck! Would love to see a picture!
    rt
     
  5. Mike C

    Mike C F1 Veteran
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  6. Steve Magnusson

    Steve Magnusson F1 World Champ
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    Jonny -- Contact Sponsor Paul Hill at Hill Engineering (check out his website).

    One point I'd make is that you might actually need to use even larger adapters than you would to just match up the tire centerlines (in order for the extra 348 wheel widths to clear the springs/shocks/A-arms, etc.). Not saying that it's good or bad, or that I know how it really looks, but in the photo mcharness posted the rear outboard tire sidewall is maxed out relative to the coachwork (if not a little beyond).
     
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  8. JonnyT

    JonnyT Karting

    Jan 21, 2004
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    Jean-Paul
    Thanks guys! The person I am buying them from is providing the spacers for another $350.00 and promises they will work. I was nervous because of the tire sizes, but apprently (at least in the picture) they will work. Do you know if any suspension work was needed?
     
  9. snj5

    snj5 F1 World Champ

    Feb 22, 2003
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    They do look good.
    Again, just be cognizant of tire sizes and diameters, as the 348 uses taller tires than the stock 308. May want to calculate diameters.

    Post some photos!
    good luck
    rt
     
  10. Dutchman

    Dutchman F1 Veteran
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    That's Wolfgang's car! Ask him in the European chat. He can definitely tell you everything about it.

    Ton
     
  11. joeyy

    joeyy Karting

    Nov 11, 2003
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    WOW!! they look great. the car has a nice look with the wheelwells full of......well.. wheel!!

    i wonder how big those spacers have to be? if they are near 2" i would be careful. these cars are driven fast and a loose spacer or broken stud at speed is NOT GOOD!!!
     
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  13. mk e

    mk e F1 World Champ

    Oct 31, 2003
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    Switching to a 2.5" OD spring helps with the tire clearance, I think you can fit about a 275 or 285. I have 285s on mine, but I moved the shock mount a little too, more for the 10.5" wheel than the tire though.
     
  14. Mike C

    Mike C F1 Veteran
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    The car in the photo I posted has been lowered... it's not just the wheels/tires that give it that look.

    Mike
     
  15. JonnyT

    JonnyT Karting

    Jan 21, 2004
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    Jean-Paul
    Then my assumption would be that suspension work does not need to be done. I would have greater clearance without a 'lowering job'. Which, in my opinion would be better.
     
  16. Dr.T348

    Dr.T348 Formula 3

    Jan 8, 2004
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    Check out the web site at Hill Engineering for a wide assortment fo spacers .
     
  17. f355spider

    f355spider F1 World Champ
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    May 29, 2001
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    Okay, I'm butting in here...but if it is really a "good deal" (search Ebay to see what 348 wheels are selling for) then I would recommend Ebaying the wheels (skip the spacers) and use the funds to purchase a set of either replica or authentic 308 QV wheels. I guess it is all personal taste, but I find the 348 wheels to look a bit odd on the 308....

    If you are after 17" wheels, then use the funds to get a set of Speedline "GTO" style wheels.

    Or, tell me to "shut up" and mind my own business... Your call. :)

    Okay, I just checked and here is a Ebay offer
    http://cgi.ebay.com/ebaymotors/ws/eBayISAPI.dll?ViewItem&category=38662&item=2454443217

    doesn't seem to be too bad a deal, but for the price, you could get new replica QV wheels with similar quality tires.

    FWIW
     
  18. JonnyT

    JonnyT Karting

    Jan 21, 2004
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    Actually...the deal is much better. A matter of personal taste, but I love the look of the 348 wheels.
     
  19. Mike C

    Mike C F1 Veteran
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    Have you thought about tire size? I just looked at my tire size calculator (it's an excel spreadsheet, if anyone is interested) and for 17-inch wheels, there are several options that will keep you at around the same overall diameter, but with different contact patches (widthds). It looks to me like 225/45-17 front and either 245/40-17 or 255/45-17 for the rears.
     
  20. JonnyT

    JonnyT Karting

    Jan 21, 2004
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    Jean-Paul
    Well folks, I made the descision and bought the wheels. They are on their way and should arrive on Monday or Tuesday. The place I purchased them from ended up having a set of 348 SPECIALE wheels that he sold me at the same price. The difference is that they have a 1" spacer already included which should work. I will let you know how it goes and if successful, I will post pics. Stay tuned...
     
  21. BrentC

    BrentC Formula Junior

    Aug 13, 2003
    278
    If you need different bolts, let me know. I have a set of Hill Engineering's 348 wheel bolts in stock and will give you a good price if you mention you are an F-Chat member. Let me know if I can help.

    Brent Cardani
    810.625.3677
    bcardani@dexmllc.com
     
  22. 348paul

    348paul Formula 3

    Dec 27, 2002
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    Johny,

    The 348 Speciale wheels use 80mm bolts on the rears, rather than the 55mm bolts. The Speciale rear wheels are like a standard 348 rear rim with an extra 25mm on the mounting face.

    Keep us posted on your progress!


    Paul
     
  23. JonnyT

    JonnyT Karting

    Jan 21, 2004
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    #20 JonnyT, Mar 25, 2004
    Last edited by a moderator: Sep 7, 2017
    Well...the progress has been slow (I received the wheels over a month ago) but I have finally received the front spacers. Here's a picture of what they look like on...
    Image Unavailable, Please Login
     
  24. tbakowsky

    tbakowsky F1 World Champ
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    You are not going to enjoy they way your car drives after this. I hate to say it, but you will have bump steer out the ying yang and the stresses on the wheel bearings is not going to be a good thing. The 348 wheel has much to different of and offset to be able to SAFELY mount them on a 308. The other thing to keep in mind is the suspension dynamics of the 308 are vastly different from the 348. You will obviously have to do an alignment but tire scrub will be a problem.
     
  25. bert308

    bert308 Formula 3
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    Nov 30, 2002
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    Wheel offsets: (from the "wheel offset" thread in the GFD section)
    308/328 PRE ABS: 7" with +11mm Front; 8" +11mm Rear
    348: 7.5" +49 Front; 9" +68 Rear

    To get the same offset a 348 front wheel will need a 38 mm spacer. With the 38 mm spacer you have the same stress on the bearings, bump steer and all other factors as with a standard wheel. The spacer in the picture looks even less than 38 mm, which is probably to compensate for the 0.5 inch wider wheel.
    The 348 9" rear wheel is listed with offset +68, that is for the standard wheel. The speciale wheel would have an offset of +43 then, 25 mm less.
     
  26. Newman

    Newman F1 World Champ
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    Dec 26, 2001
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    You are right Tom, the first thing that came to mind once I saw those big honkin spacers was the scrub radius change. It will hurt handling for sure.
     
  27. mk e

    mk e F1 World Champ

    Oct 31, 2003
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    I'm going to vote with Bert. What's important for handling is the wheel centerline, not where the hub face is. In this case, the spacer is required to keep the wheel centerline in the stock location and preserve the handle/steering. Not using the spacer with would move the wheel in and really mess things up. The only bad things the spacer will do is add a little weight and put more load on the wheel bolts, but thet have a huge safety factor, so I can't imagine it being a problem.

    I run a set of 550 wheels on my car and the fronts have an offset of 46mm compared the the stock 11, so a 35 mm spacer would be need to keep the centerline in the stock location. But the wheels are 8.5" instead of 7", they would stick out 20mm farthere than stock [ (8.5-7)"/2*25.4= 20mm], and I was afraid they would rub, so I split the difference moved the centerline in 10mm by making the spacer 25mm. It seems fine.
     
  28. Auraraptor

    Auraraptor F1 World Champ
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    Sep 25, 2002
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    Hmm this is an interesting discussion about centerlines.

    Since I am putting 360 wheels on my car, the centerline in the rear is offset by about 32-33mm outward. The front centerline is almost dead on the same. The rear though makes me wonder.

    What should I expect? (aside from more understeer, and a less firm/taut stuspension feeling)
     

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