Front brake option

TonyK said:
I think we have a winner here.
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Tony, nice work. So the Pop rotors are centered in the calipers/pads without modification to adjust that dimension?


Mark said:
are the calipers, pads and pad holders all from the 500Pop as well
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Mark, I'll let Tony confirm the specifics, but I understood these were Abarth calipers and holders - only the rotors are Pop.

However I believe the Pop and Abarth calipers and holders are interchangable? Seems I've read that it is possible to bolt Abarth calipers onto a Pop? But if the rotor hats are different height, then that might not be true? Tony, do you know about that? Does it have to specifically be Abarth calipers/holders to align with the Pop rotors (without further mods to center them) on the X?
 
Dr.Jeff said:
Tony, nice work. So the Pop rotors are centered in the calipers/pads without modification to adjust that dimension?



Mark, I'll let Tony confirm the specifics, but I understood these were Abarth calipers and holders - only the rotors are Pop.

However I believe the Pop and Abarth calipers and holders are interchangable? Seems I've read that it is possible to bolt Abarth calipers onto a Pop? But if the rotor hats are different height, then that might not be true? Tony, do you know about that? Does it have to specifically be Abarth calipers/holders to align with the Pop rotors (without further mods to center them) on the X?
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For the record. I have 2 complete Abarth's at home, so I have both Abarth rotors (283MM) and Abarth Calipers. The Abarth Rotors are too big for the X1/9 as they sit too far inboard on the hub and also the pad carrier does not clear the extreme of the rotor. The POP rotor (257MM) works without modification. I think the front calipers are the same on the Pop and Abarth, but would have to check as my son has a Pop.

TonyK.
 
TonyK said:
I think the front calipers are the same on the Pop and Abarth, but would have to check as my son has a Pop.
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Thanks again Tony. As I said earlier, I also thought the calipers were the same for both models. However it seems to me if the rotors have different offsets (not the outside diameter, but the height of the mounting surface relative to the disc), then there must be a difference in either the caliper, the hanger bracket for the caliper, or both. Otherwise both rotors would be centered midline with the caliper. Follow what I'm thinking? I'm curious which components are different between those two models (other than the rotors). Appreciate if you are able to compare them to see - great that you have access to both models, as having parts to work with is half the battle. Thanks
 
Looking at Rock Auto the 500 Pop caliper and pad carrier are smaller. I will look at my son's car this weekend and remove the carrier to see if it bolts on to the X1/9 Knuckle. If it doesn't and looking at the pictures it does not look like it will, we may have to accept the fact that a mish mash of 2 different models will be required to make this work. The Pads on the Abarth are significantly larger than what is on the Pop. That larger surface area of the pad may work to our advantage without power brakes giving a bit better front braking without lock up.

TonyK.

Grimsby Ontario Canada.
 
Some good detective work here. I'm guessing you would need a minimum of 15" wheels to clear these? I would think you may want to up grade the rear brakes to get the same front/rear balance as before. (Bigger pistons, 54mm? and larger diameter rotors)
I was thinking along the lines of 240mm x 20mm vented rotors and 48mm piston calipers from a European 74hp diesel engined 500. But from your experimenting it sounds like the carrier mounting position is different between an X19 and a 500. It may need our friends in the UK to do some experimenting. Then of course, there is the cost of importing heavy components.
 
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I've been looking at parts listings on various web sites. Gets a little vague; some indicate different components for certain year groups (although that does not necessarily mean they are different parts), some don't even show Abarth listings, while the listings on some sites contradict that from other sites, etc. I think part of the problem is the US version of 500's may have different brake components than the European (and other) markets.

Regardless, I'm guessing the caliper brackets (pad hangers, caliper mounts, carriers, whatever you prefer to call them) for all normal (non Abarth) models is different than the Abarth ones - due to the rotor difference (noted previously). However, the calipers themselves may fit both brackets/carriers (standard and Abarth)? Not sure though.
I think the calipers and brackets/carriers from the standard 500 should fit onto the X's spindle/upright the same - at least as far as mounting goes (just need to enlarge the holes). But their offset (rotors centered in the calipers) would likely not be right. But that would explain the Abarth brake "upgrade" for regular 500's; swap the calipers and rotors and they would fit the standard models.

I think Tony might be correct that a combination of Abarth carriers (and/or calipers) and standard rotors seems to be the combination that works on the X. Tony, please let us know if you are able to verify the caliper and/or carrier question (Abarth vs standard).

On a different note. How about using 500 brakes on the X's front, and X1/9 front brakes on it's rear? Obviously that eliminates the stock park brake arrangement (which might be a good thing), but there are other options for a park brake. It also does not completely do away with the "sliding wedge" design, but at least this way it is only on the rear. That might offer a better front - rear caliper size combination? And it would be a easy and affordable 'big brake' kit.
 
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Hey GregS, I mounted a 14" Maserati Biturbo wheel to my Scorpion briefly after mounting up the Abarth 500 front calipers with 260mm rotors in front and 257mm rotors in the rear. Cleared them no problem, I have a set of Alfa Romeo Cromodoras in 14" that I will check as well...

Still going to check the piston size of my wife's new Fiat 124 rear brake calipers to see if there's an increase over the Abarth 500 rear calipers too.
 
Tony, sorry if this has been covered but how are you going to bleed the caliper if it is facing down? At least I think that is how I understood it?

I guess you can make a spacer to hold the pads and piston in place, flip the caliper up and bleed it.
 
Maybe I didn't understand everything correctly.
But isn't it possible to swap calipers from left to right and from right to left - then hose wont't be on top?
 
motoTrooper said:
Still going to check the piston size of my wife's new Fiat 124 rear brake calipers to see if there's an increase over the Abarth 500 rear calipers too.
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I wonder if the new Spider has Fiat brakes or Mazda brakes? Is it a 4x98 bolt pattern or a Mazda pattern (not sure what they have, maybe 4x100)?

Glad you joined this discussion, as you are the only person that I recall with the New 500 brakes already installed on a old Fiat (Scorpion, but same as X1/9). The rotors you have are not stock 500 items, so the diameter and offset was different. Do I remember correctly that you slightly moved the rotor's position (relative to the caliper centerline) by adding shims ("stop sign") between the hub and rotor?
 
Most (not all) caliper mounts allow a left or right caliper to mount into the carrier. Some caliper carrier assembly’s are handed top to bottom by the caliper bolt in the the slider mechanism. I don’t think the 500 carrier/caliper have this issue.

I suspect Tony just put the wrong one in the carrier as it was the one he had most accessible.

That or he wanted to see if we were actually paying attention :)
 
Mototrooper, good to hear at least some 14" fit, although I am still wanting to use 13". I tried one 13" on the rear of a 500 with 240mm rotors, and they were fouling on the calipers, but may be the style of wheel, or needed a thicker wheel spacer. 500 rotors are offset outwards compared to an X.
Are the front hubs etc on a Scorpion the same as an X?
What size master cylinder are you using?
 
mkmini said:
Maybe I didn't understand everything correctly.
But isn't it possible to swap calipers from left to right and from right to left - then hose wont't be on top?
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The calipers are symmetrical, I just grabbed the wrong side for fitment in the pictures. One issue I looked at today is that the caliper will either need to be tapped or adapters or custom hoses will need to be made as the threads on the caliper and the hose end do not match what is on the X1/9. Personally I think when Bob's car is here I will machine the caliper and install a banjo bolt fitting like I did on the UNO TURBO front calipers currently on my Abarth X1/9. The rears of the car have the larger aftermarket calipers that required the pistons to be remade or sleeved as they are only made from soft steel bar stock and not chrome plated.

TonyK.

Grimsby Ontario Canada.
 
lanciahf said:
Tony, sorry if this has been covered but how are you going to bleed the caliper if it is facing down? At least I think that is how I understood it?

I guess you can make a spacer to hold the pads and piston in place, flip the caliper up and bleed it.
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Read post 59.

TonyK.

Grimsby Ontario Canada.
 
TonyK said:
the caliper will either need to be tapped or adapters or custom hoses
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Since you have to change the hose attachment anyway. Personally I'd tap the calipers to use standard (US) size fittings. Then I'd cut off the ends of the hard lines leading up to the calipers and reflare them using standard size nuts and US type flare. That way you can use normal stainless braided hoses that are commonly available inexpensively, any length with straight or 90* ends. Example:
https://www.speedwaymotors.com/Braided-Steel-AN-25-Inch-Brake-Line,687.html
 
Dr.Jeff said:
Since you have to change the hose attachment anyway. Personally I'd tap the calipers to use standard (US) size fittings. Then I'd cut off the ends of the hard lines leading up to the calipers and reflare them using standard size nuts and US type flare. That way you can use normal stainless braided hoses that are commonly available inexpensively, any length with straight or 90* ends. Example:
https://www.speedwaymotors.com/Braided-Steel-AN-25-Inch-Brake-Line,687.html
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Looking into this a bit further ideally I would like to drill out the caliper and use the stock X1/9 Banjo bolt hose and fitting. That way if things go south I can put the stock X1/9 calipers back on the car without much issue. I will turn a set of sleeves 10mm-12mm to compensate for the drilling out of the pad carrier holes on the knuckle. To me this would be the simplest way to make all of this fit and still have the option of going back to Stock.

TonyK.

Grimsby Ontario Canada.
 
TonyK said:
I will turn a set of sleeves 10mm-12mm to compensate for the drilling out of the pad carrier holes on the knuckle.
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If you intend to keep it reversible (back to stock), then how about use the sleeves (10mm to 12mm) on the caliper carriers. Then use 10mm mounting bolts and not drill out the X knuckle.

By chance did you determine if there is any difference in the Abarth vs stand 500 caliper brackets, or is it the calipers themselves that are different (I'm referring to the offset)? Thanks.
 
Tony, in addition to the question I just asked above....

Thinking back at the use of the "Pop" 257mm rotors vs "Abarth" 283mm rotors.
Two things I'd like to verify:
1) Does the smaller overall diameter of the Pop rotors seem to present any possible issue with brake pad to rotor contact? Here is what I'm referring to...
IMG_0778.JPG


Question 2) The offset difference between the two rotors was 3mm? And that is between the wheel mounting surface and rotor face?

Thanks again, I'm still thinking through a bunch of options about all this.
 
Dr.Jeff said:
Tony, in addition to the question I just asked above....

Thinking back at the use of the "Pop" 257mm rotors vs "Abarth" 283mm rotors.
Two things I'd like to verify:
1) Does the smaller overall diameter of the Pop rotors seem to present any possible issue with brake pad to rotor contact? Here is what I'm referring to...
View attachment 19972

Question 2) The offset difference between the two rotors was 3mm? And that is between the wheel mounting surface and rotor face?

Thanks again, I'm still thinking through a bunch of options about all this.
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1) I think with regard to brake pad to rotor contact as the pads wear a slight lip will appear on the pad rather than on the rotor outer extreme.

2) Correct the rotor moves out board which allows it to clear the pad carrier. It is not perfectly centered but I think it will work.

TonyK.

Grimsby Ontario Canada
 
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