Wheel Bolt Patterns

[SamF]

OK another newbe question:

I am getting ready to convert my rear drum breaks to disks and it seems that I can get predrilled break disks that are 4X4 or 4X130 bolt pattern, or I can drill my own to 4X100 or 4 X??. Is there a preferred bolt pattern? Is there a benefit in wheel choices one may have over the others?

[kea]

I would think that you would want the same wheel bolt pattern, front and rear, so unless you plan to change the front, your question about what pattern for the rear appears to be answered.

[SamF]

Well I will need to change the front drums as well to disks when I add the ball joint beam, and then it will match the bolt pattern I pick for the rear. I am just starting the conversion from the rear forward, or something like that.

[kea]

[DanW]

Well I will need to change the front drums as well to disks when I add the ball joint beam, and then it will match the bolt pattern I pick for the rear. I am just starting the conversion from the rear forward, or something like that.

Have you looked into what wheel bolt circle in 13x6 is available in reasonable quantities? The other important dimensions are backspace/offset and caliper cleearance.

Wheels drilled with 130mm BC are plentiful if you want 15" rims but are often specials in other manufacturers in 13". Perhaps contacting SRacing or other FST suppliers might provide you with the answers you need.

Regards,
Dan Wise
(who just had a 13x5.5 revolution plugged and drilled to 130mm to complete a set)

[rickjohnson356]

Seems that most FST use 4x100 bolt pattern.

I have 4 real minilites (not panasport) left over from my 1970 FSV which are 13x6 and had a 4x130 pattern.

Sent them to Wheels America and got them drilled for 4x100-- they look great

(ps: they still weigh in at just over 10lbs)

I guess being a pack rat pays off sometimes, 40 years later....

I would stay with 4x100 because most suppliers have that pattern.

PSS: see if you can find some old BBS basketweave wheels for a BMW 2002, mine are 13x6 and 4x100--

no longer on my 1973 round taillight 2002, but ready for some Hoosier slicks on my FST

[Bob VanDyke]

OK another newbe question:

I am getting ready to convert my rear drum breaks to disks and it seems that I can get predrilled break disks that are 4X4 or 4X130 bolt pattern, or I can drill my own to 4X100 or 4 X??. Is there a preferred bolt pattern? Is there a benefit in wheel choices one may have over the others?

Most of the FST guys are on their way to the ARRC right now, however, they generally use 4x4 bolt patterns. From the FST rules:

4.1.2. Wheel bolt pattern is free, except that it must use 4 lug bolts or studs with lug nuts. No centerlocks. As a recommended standard, the common bolt pattern for Formula First is 4"x 4 bolt.

If you use 4x4, you should be able to easily borrow a wheel from someone at the track if needed.

[problemchild]

Also, note that when you buy the pre-drilled 4X130mm rear discs, they will likely be configured for the longer axles and will need 10mm or so machined of the ouside of the hub (on a lathe).
As horrific as it sounds, many of the early discs were drilled and tapped 4X4" by hand, and they worked just fine.
If redrilling the 4X130mm discs, it is better to rotate just enough to clear the existing holes, rather than spacing it nicely in between. This avoids drilling and tapping into irregularily spaced cast ribs on the interior of the disc (on the fronts anyway). Rotating only several degrees leaves you in a meaty section that will be flat on the interior and much friendlier for boltheads or locknuts.
Finally, those rear discs are really crappy and need to be overtightened to stay tight. If you do have one loosen up, order another one because you will be putting it on soon. The good news is they don't break and are cheap!

[tim67]

When I converted I choose 4x4 thinking I could get a spare from the Ford guys. Their wheels are 5.5 not 6 so choose carefully. Aero quit making 13" wheels but Bassett are available. Also if you can find some old BBS 13x6 320 wheels at 4x100 they are easily re drilled. I had a mill set up and indexed to drill only the 60 degree nut seat theywork well and look great. Rember if you choose some of these cast wheels you will need spacing to get the right offset. Which brings up longer hi tensil studs.
Everything Gregg said about re drilling the rotors is ACCURATE; I bought some from one of our major suppliers and they were redrilled so the stud heads didnt sit flat on the inside of the rotor so they splayed outward.

[problemchild]

I made 4" long studs from quality (grade 8 I think) 7/16 threaded rod and never had any issues. Blue locktight and a jam nut inside .... again never an issue. I expect the disc material is so crappy .... that you will pull the stud through it before you will damage a stud

[jsteeb]

I drilled mine 4 x 4. But, only because of the sentence quoted above.

If I had it to do over, I would drill it 4 x 100mm.

IMHO, the latter gives more options. 13x6 is already a fairly unique size, and I think 4x4 narrows it down even farther. The only OEM's I can find with 4x4 are some of the older British cars. But, 4x100 and 4x130 have been popular in OEM'land for a long time.

Just my $0.02.

Cheers!
Jason

[problemchild]

cosworth Vega

[jsteeb]

hahaha...true.

gotta love google.

So there are some. Do you know if those were 13x6? I always assumed they were 13x5.5.

I'd still go with 4x100 tho.

[problemchild]

I bought Cosworth Vega wheels on Ebay. They were 13X6 but weighed 17 lbs each. Sold on Ebay. I thought the Diamond wheels were the lightest and best quality of the "stock car" wheels ... and lighter than any OEM wheels.

[gwizdek25]

When I converted I choose 4x4 thinking I could get a spare from the Ford guys. Their wheels are 5.5 not 6 so choose carefully.

Then why does FST use the 6" wheel and not the 5.5"? Wouldn't it make more sense to go with what the FF guys use?

Thanks,

Mike

[SamF]

Thank you all, so now I am down to picking between 4X4 or 4X100. Leaning towards 4X4 since I can buy the ready to go from Jim.

What is the back spacing is needed on the 13X6 wheels?

[problemchild]

Mike's question: Ongoing discussion. The argument was to avoid people being able to sneak lightweight FF wheels on the cars. There is a minimum weight but its a PITA to do eligibility tech on wheel weight. There are many nice steel wheels available from the oval racing market in 13X6 with 4X4" BC at well under $100 each. That is a set of wheels for $100 less than one OZ FF wheel! The rule maintains a cheap wheel philosophy.

Most of the OEM wheels that might be used are uncompetitively heavy and only desirable for appearance value.

[rgu]

If you were at the ARRC this weekend and you bent a wheel you could borrow one easily if it was 4x4, Anything else and you had better bring spares.

To my knowledge no one has had a disk issue (with one exception) in the past three years. This covers a lot of disks.

[jsteeb]

RG and Greg both make pretty good points.

My main reasoning for suggesting 4x100mm is the availability of aftermarket wheels. My, pipe dream(?) is that there might be a cheaper alternative to the wheels we are all using. Pana's and Revo's look cool, but they are not cheap. The other option is the Nascar steel wheels. Call me an open-wheel snob or whatever, but I just don't like them. Maybe it's because I'm part the generation which brought you drifting, but personally, I would love a 14 or 15" wheel. Of course I wouldn't trade the larger wheels for the awesome tires we have, so....

Anyway...Greg's point about weight should be considered, and is one I am starting to give up on. Any/All of the wheels I am hoping to find would be designed and manufactured for street car use, and probably weigh significantly more than a Pana or Revolution.

RG's point about spares is also worth noting. I think most have a dry set and a rain set...but it would really suck to miss a race because of a bent wheel.

It might also be worth noting, most of the 13" wheels I have found, with a 4x100 bolt cirlce are only 5.5" wide. Another setback in the hunt for an alternative.

Jeez...I'm starting to talk myself back into 4x4.

Hope to see you out there next year!

Cheers,
jason

[kea]

Jason,
Remember this, the F/Ford tires were designed around a 13"X5.5" wheel. I'm not sure anything is really gained using a 6" wheel and "club" tires.

[Bob VanDyke]

There were talks about setting the wheel width at a maximum of 6 inches to allow use of 5.5, but nothing came of it. Now that the SCCA is controlling the rules of the class, if anyone feels strongly enough about it they could submit a request to change it.

[SamF]

OK 4X4, with steel wheels it is, now I just need to spend the money.

What are the thoughts on back space needed on the wheels??

[sracing]

OK 4X4, with steel wheels it is, now I just need to spend the money.

What are the thoughts on back space needed on the wheels??

"Needed" Backspacing may help to clear the caliper in some cases or you can usually grind off a bit to make sure they clear. There is no requirement for backspacing, but it can be used to meet the track measurement rules.

[SamF]

Thanks Jim,

I'll be driving down this week to go shopping, I'll give you a ring to confirm

Sam

[sracing]

Ok Sam, We will be here.

Jim
SR

[samiam520]

Pretty sure the FF bolt pattern is 4 x 3.5"