FXRS rear brake caliper update : V-Twin Forum: Harley Davidson Forums

1970pelle · 11-27-2012, 08:20 PM

while I have my FXRS apart installing to wide glide front end. Which will have the 2000 up 4 piston caliper. After some checking I found that my 5/8 bore rear master cylinder will work a 4 piston caliper just fine. I Had picked up a caliper at a swap meet for a deal. Freshed up the paint and bolts. I removed my old unit. I had to find a spacer to bring the caliper mounting hole to 3/4 inch. Ace Hardware has the spacers,only needed a small amount of trimming to fit lenght wise. I made my caliper stop out of alumn stock cut and shaped to fit the swing arm. I drilled 1/4 holes in bracket and swing arm. Then used a piece of steel cut to size to fit inside the swing arm,with two matching holes with two 1/4 nut tack welded to the steel bracket.Then bolted everything together. Pictures. Ken

ALAY191 · 11-27-2012, 09:56 PM

looks great Ken!

V-STRUM · 11-28-2012, 06:38 AM

Looks clean without the large bracket that holds the stock caliper. I have a pair of 4 piston calipers up front, a nice improvement, but stayed with the stock caliper out back.

kdkerr2 · 02-02-2013, 02:58 PM

This is a good upgrade for all FXR's. The stock caliper had several issues. The 00 and up 4 piston caliper is a lot more effective. I'm fairly certain this caliper came off an 00+ Dyna Glide or an Electra Glide. The main thing to check is to make sure the wheel spacer and the caliper bracket thickness is the same as before. Otherwise your wheel will be offset and the rear pulley will eat up your drive belt!

kdkerr2 · 02-02-2013, 03:10 PM

This is a good upgrade for all FXR's. The stock caliper had several issues. The 00 and up 4 piston caliper is a lot more effective. I'm fairly certain this caliper came off an 00+ Dyna Glide or an Electra Glide. The main thing to check is to make sure the wheel spacer and the caliper bracket thickness is the same as before. Otherwise your wheel will be offset and the rear pulley will eat up your drive belt!

FXR Nut · 02-02-2013, 03:38 PM

I have no intention to hijack this thread but... Can anyone explain to me why additional braking power is needed for the rear?

I am all about strong front brakes but I never needed more than a stock HD single caliper for the rear.. It's all too easy to lock the rear with stock brakes..

I come from a motocross background, have been riding over 30 years, and never found the rear brake very useful on a street bike... I always leave rear brakes stock, how much does it take to lock up a rear wheel? Too much rear brake will lose control,

I replace front pads 4 to 1 so not alot of rear brake used...

I am not trying to stir up this thread rather curious and open to opinions on why strong rear braking is needed...

ALAY191 · 02-02-2013, 10:53 PM

Quote:

Originally Posted by FXR Nut

I have no intention to hijack this thread but... Can anyone explain to me why additional braking power is needed for the rear?

I am all about strong front brakes but I never needed more than a stock HD single caliper for the rear.. It's all too easy to lock the rear with stock brakes..

I come from a motocross background, have been riding over 30 years, and never found the rear brake very useful on a street bike... I always leave rear brakes stock, how much does it take to lock up a rear wheel? Too much rear brake will lose control,

I replace front pads 4 to 1 so not alot of rear brake used...

I am not trying to stir up this thread rather curious and open to opinions on why strong rear braking is needed...

I noticed much better feel to the late model 4 piston caliper compared to the earlier stuff. I did that conversion on my Shovelhead. Changed only the caliper and left rotor and MC untouched. Sure, its just as easy to lock up the wheel when I want to, but I can also brake harder now without locking it up.

kdkerr2 · 02-02-2013, 11:16 PM

One of the issues with the old FXR rear caliper was that after several years things on the caliper or the bracket could start wearing assymetrically. New parts are now hard to locate so using the newer 4 piston caliper is a good solution for this problem since they aren't nearly as hard to locate on Ebay or at swap meets. They will give increased stopping power which is probably not needed. Harley did stop using the rear 4 piston caliper on Sportsters and went to a 2 piston set up.

FXR Nut · 02-03-2013, 06:12 AM

Ok, I get it, so the braking is more accurate this way... Makes sense, also more reliable..

kdkerr2 · 02-03-2013, 09:57 AM

The original rear FXR calipers [and FLT, I think] were free floating with rubber grommets to isolate the caliper. They didn't always stay tracking correctly and could get out of position and wear things [pads] assymetrically. The newer four piston calipers were solid mounted and never moved around and everything stays tracking correctly, a superior system. By the way, the FXR4 the last FXR's ever made came stock with these four piston calipers front and rear.

kdkerr2 · 02-03-2013, 11:32 PM

Here's how I upgraded my rear brake assembly. I used an Italian Grimeca 41mm 1050/55 twin piston caliper which I bought from Storz Performance in California. The stock Harley master cylinder makes the caliper lock the rear wheel if you get on it too hard! So you got be real gentle about it if you don't wish to go fishtailing all over the street! I had to build my own mounting bracket from billet and that was a pain in the butt but you got to do what you got to do! The stabilizer part is almost a complete copy of a stock FXR rear brake bracket including the rubber bumper which keeps the bracket from flopping on the swing arm.

1970pelle · 02-07-2013, 09:52 PM

I apologize about the photo's being deleted in post #1. I was updating my Photobucket stuff and moved stuff around. There back up. Ken

kdkerr2 · 02-07-2013, 10:12 PM

When installing this 4 piston caliper, what did y'all do about the width of the new caliper bracket?. Was it the same as the ones on the original FXR caliper bracKet [in thickness] or did you have to trim it down or add shims if it was too narrow?

1970pelle · 02-10-2013, 02:08 AM

I lucked out on that. I have a stack of shims from another project,that were 3/4 ID. But I had to cut the OD to size.I don't remember off hand the measurement in the .030-.040 range. I almost could have gotten away out any. KA

tussuck · 02-10-2013, 03:50 AM

Is there a thread someone can point me to for front brake upgrades? I tried like he'll to lockup my I'd 86 FXR front end and absolutely no joy....so some thing needs to be done.
Cheers

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