Whoa brakes on CD-39 wheels

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miker
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Whoa brakes on CD-39 wheels

Post by miker » Tue Jan 29, 2019 10:17 pm

I'm embarking on a quest to adapt larger than stock rotors for my CD-39 wheels with the Whoa kit. I suspect that the 14" Pininfarina rotors at 257mm will be too large, and the spacers to accommodate them that Midwest Bayless sells will be too long; i.e. the calipers will run inside the wheel. But I think it's close.

I found some 250mm rotors that Chris Obert sells for Ritmos and they were super inexpensive so I got a pair. They are also a too thick at 10.8mm (I didn't pay attention to that when I ordered them). I can have these turned or they do make 9.5mm 250mm rotors (P/N 4377102).

Have not sourced spacers yet that are 2.5mm shorter than those in the Whoa 14" kit yet.

I'll report back when I know more.

I think there are a fair number of people who would like larger rotors with 13" wheels.

MikeR
MikeR (mirafiori.com since 1995)


1977 Fiat 124 Spider
Previously owned:
2012 Fiat 500 Prima Edizione #236 (now owned by my son David)
'86 Bertone X1/9
'81 Fiat Spider 2000 #236
'78 Fiat 131 four door
'76 Fiat 128 4 door
'74 Fiat 128 4 door
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friedman
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Re: Whoa brakes on CD-39 wheels

Post by friedman » Wed Jan 30, 2019 8:56 am

When Jim Fierst was developing the WHOA brakes, a big issue was what 13" wheels would fit. He sent me a set up and John Erskine and I tried a whole bunch of wheels and sent a list to Fierst. I don't remember which wheels fit and which didn't. This was with stock rotors and in a few instances the fit was so close I had to do some minor clearancing on the calipers. I know I had the WHOAs on about three Fiats, all using 13" wheels of various manufacture. Going to larger diameter rotors is going to knock out a lot of 13" wheels but it's something you will have to figure out on your own unless you are lucky enough to find someone with the same brake setup you have and the same wheels.

And don't plan on using stick-on weights on the inside of the wheel rim, they will definitely hit the caliper.
Carl in Virginia
75 spider
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Re: Whoa brakes on CD-39 wheels - larger rotors work!

Post by miker » Wed Feb 13, 2019 9:48 pm

I ordered the complete upgrade kit from Midwest-Bayless - their larger rotors, longer caliper bolts and spacers. I can state definitively that the larger rotors work with the CD-39 wheels. Yay!

One odd thing- not withstanding the online specs, the rotors I got from Obert mentioned above seem identical in diameter and thickness to the ones I got from Midwest-Bayless. YMMV.
MikeR (mirafiori.com since 1995)


1977 Fiat 124 Spider
Previously owned:
2012 Fiat 500 Prima Edizione #236 (now owned by my son David)
'86 Bertone X1/9
'81 Fiat Spider 2000 #236
'78 Fiat 131 four door
'76 Fiat 128 4 door
'74 Fiat 128 4 door
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miker
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Posts: 4081
Joined: Sun Jan 24, 2016 7:55 pm
Last Name: Richmond
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Re: Whoa brakes on CD-39 wheels

Post by miker » Thu Feb 21, 2019 12:58 pm

My CD-39 wheels have stick-on weights on the inside and they do clear the calipers!
MikeR (mirafiori.com since 1995)


1977 Fiat 124 Spider
Previously owned:
2012 Fiat 500 Prima Edizione #236 (now owned by my son David)
'86 Bertone X1/9
'81 Fiat Spider 2000 #236
'78 Fiat 131 four door
'76 Fiat 128 4 door
'74 Fiat 128 4 door
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