Kool-Stop Fit Issues: Rod brake + John Bull pads undersized
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Kool-Stop Fit Issues: Rod brake + John Bull pads undersized
I was originally going to post this in my 1945/6 Humber build thread, but held back until Kool-Stop had a chance to reply. They've since replied...and, well - read on:
Back in 2019, I discovered Kool-Stop had begun producing direct-replacement John Bull brake pads; direct replacements for many 1960's Raleigh and Raleigh-produced 3-speeds.
At the time, I didn't have a need for them, but with the Humber in need of some replacement rod brake pads - which Kool-Stop also makes - I thought I'd get a set of each and give them all a try:
To my surprise, I found both the rod brake pads and the John Bull pads fit terribly loose in their holders:
The John Bull #25 replacement:
Unfortunately, I don't have an original John Bull to compare against (the holder had a generic Japanese replacement, and I can't find it at the moment), though if anyone has one they can lend for a side-by-side, I'd appreciate it.
The rod brake replacement in the wartime holder at right, compared against an extra-long 1950's holder with a Fibrax 70/2 in it:
For a more conclusive comparison, here's the Kool Stop rod brake pad compared with the pad that came out of the wartime rod brake holder:
It's as if every dimension for the holder area is undersized. Yes, I realized these are supposed to be crimped to an extent, but a proper fitting pad should fit snug to begin with. If I were to "crimp" the wartime rod brake holder, I'd probably make it nearly unusuable for the next time around.
I brought these issues to Tim, from Kool-Stop, who replied as follows:
I disagree - but I'd like to hear if the forum agrees or disagres with Tim's counterpoint. Personally, I don't think there's any more practical crimping to be had on that John Bull holder. There's a limit to how much one can crimp these before ruining the holder. The JB holders are made out of some pretty stout steel that doesn't bend easily without causing the outer surface of the holder to bow - something that is not required when fitting any period replacement pad of the proper size. To even suggest that it's within any tolerance of fitting - especially since they've seen these photos - is a joke, in my book. Same for the rod brake holder.
I'd argue that the obvious cross section difference between the rod brake pads is only further indication that Kool-Stop has undersized their measurements.
I'm curious to hear what others think, based on these photos, and would be open to anyone who wants to add to the comparisons with their own pads and holders. Likewise, I'd be more than willing to cover shipping to and from to check additional original pads and/or holders against the Kool-Stops.
I've sent Tim this thread, FYI.
-Kurt
Back in 2019, I discovered Kool-Stop had begun producing direct-replacement John Bull brake pads; direct replacements for many 1960's Raleigh and Raleigh-produced 3-speeds.
At the time, I didn't have a need for them, but with the Humber in need of some replacement rod brake pads - which Kool-Stop also makes - I thought I'd get a set of each and give them all a try:
To my surprise, I found both the rod brake pads and the John Bull pads fit terribly loose in their holders:
The John Bull #25 replacement:
Unfortunately, I don't have an original John Bull to compare against (the holder had a generic Japanese replacement, and I can't find it at the moment), though if anyone has one they can lend for a side-by-side, I'd appreciate it.
The rod brake replacement in the wartime holder at right, compared against an extra-long 1950's holder with a Fibrax 70/2 in it:
For a more conclusive comparison, here's the Kool Stop rod brake pad compared with the pad that came out of the wartime rod brake holder:
It's as if every dimension for the holder area is undersized. Yes, I realized these are supposed to be crimped to an extent, but a proper fitting pad should fit snug to begin with. If I were to "crimp" the wartime rod brake holder, I'd probably make it nearly unusuable for the next time around.
I brought these issues to Tim, from Kool-Stop, who replied as follows:
When we built the tooling on the rod pull we used the best NOS holder from a collector that send several pieces into our factory. We know that the holders are meant to be hand crimped on each end when new rubber was inserted. There is a possibility that new molding tooling was made in different spec's (thus your pads and holders shown)
The John Bull holders that you have show look like they also will need to be crimped with pliers once the pads are set to depth. Can you send in more images one you have the holders crimped shut?
The John Bull holders that you have show look like they also will need to be crimped with pliers once the pads are set to depth. Can you send in more images one you have the holders crimped shut?
I'd argue that the obvious cross section difference between the rod brake pads is only further indication that Kool-Stop has undersized their measurements.
I'm curious to hear what others think, based on these photos, and would be open to anyone who wants to add to the comparisons with their own pads and holders. Likewise, I'd be more than willing to cover shipping to and from to check additional original pads and/or holders against the Kool-Stops.
I've sent Tim this thread, FYI.
-Kurt
Last edited by cudak888; 08-08-21 at 12:24 PM.
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My only guess is that the dimensions of the pads and holders changed over time. The only thing I have to go by is that the Kool Stop rod brake pads fit about as good as can be into the holders on my mid-'70s Tourist - nowhere near loose like the image you showed. Perhaps the sample holders Kool Stop was working off of were later production than what you have?
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I have a '74 DL-1 with red Kool Stops. A perfect fit for me, nice and tight. BFisher may be right on dimensions changing over time. Seems unlikely, but....
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My only guess is that the dimensions of the pads and holders changed over time. The only thing I have to go by is that the Kool Stop rod brake pads fit about as good as can be into the holders on my mid-'70s Tourist - nowhere near loose like the image you showed. Perhaps the sample holders Kool Stop was working off of were later production than what you have?
I'm still on the fence about those John Bulls though. The #25 pad, to my knowledge, never changed dimensions.
-Kurt
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That’s a bummer, I recently saw those as listed and could use fresh pads on my 1964 roadster with rod brakes.
they took the best info they could but visibly looks different than yours.
might consider a brass shim.
extra work.
they took the best info they could but visibly looks different than yours.
might consider a brass shim.
extra work.
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Ok, pulled the holders off the '79 DL-1. These are capped at both ends and required a bit of bending to open up.
I see no major difference in overall girth from the wartime holder. In fact, it looks slightly fatter.
Photo below: Kool-Stop in prewar holder, '79 holder w/original pad, Kool-Stop w/o holder:
I didn't try undoing the 79 pad from its holder, as it has a couple of extra pinch points built into it. But even the side-by-side with the Kool-Stop above suggests it'd be a very loose fit.
@BFisher - do you have photos of your holders, by chance?
-Kurt
I see no major difference in overall girth from the wartime holder. In fact, it looks slightly fatter.
Photo below: Kool-Stop in prewar holder, '79 holder w/original pad, Kool-Stop w/o holder:
I didn't try undoing the 79 pad from its holder, as it has a couple of extra pinch points built into it. But even the side-by-side with the Kool-Stop above suggests it'd be a very loose fit.
@BFisher - do you have photos of your holders, by chance?
-Kurt
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I recall these being a nice snug fit. Both ends are open on these holders - no caps. I had to open up the rears a tad for installation, left the front facing ends crimped.
Last edited by BFisher; 08-08-21 at 04:07 PM.
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If so, they're probably backwards. Can't tell for sure.
-Kurt
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That's the end toward the back of the bike, front wheel. Both ends actually were crimped when I did the pad change. I opened up the ends that face the rear, and left/tightened slightly the ends that face the front. Prying them open was a bit tougher than I expected. The pads went in snugly with a little soap to help along.
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That's the end toward the back of the bike, front wheel. Both ends actually were crimped when I did the pad change. I opened up the ends that face the rear, and left/tightened slightly the ends that face the front. Prying them open was a bit tougher than I expected. The pads went in snugly with a little soap to help along.
-Kurt
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Looks like I misspoke in my case. I remember them going very snugly, but it looks like that was at the pinch points. Here's a fore-and-aft shot, it's definitely a bit loose in the rear. They brake well though, no motion.
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Find another manufacturer. Problem solved.
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-Kurt
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Interesting. I'm trying to ascertain whether these are the same holders or not at this point - @BFisher, do you have a photo of the front of your holders, similar to @PilotFishBob's picture?
-Kurt
-Kurt
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My speculation would be that the holders Kool Stop received and used for these reproductions might have been crimped more than normal. Thus leading to the undersized pads you received. Might there be a practical way to shim the pads as you insert them into the holders? Possibly, thin aluminum strips from a beverage can?
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My speculation would be that the holders Kool Stop received and used for these reproductions might have been crimped more than normal. Thus leading to the undersized pads you received. Might there be a practical way to shim the pads as you insert them into the holders? Possibly, thin aluminum strips from a beverage can?
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No pic at the moment, but I can say that the front looks exactly like the rear but with the corners pinched inward.
Currently I don't know of another replacement pad producer for these pads. Given that, if it was me I would find a piece of round stock the diameter of the Kool Stop pad insert section and reform the holder around it - close it up a tad. Grab a couple pairs of pads and be good for a lifetime. I also wouldn't hesitate to make the John Bull holders fit if I was confident it would work without mangling things. Who else is making replacement pads for them?
Currently I don't know of another replacement pad producer for these pads. Given that, if it was me I would find a piece of round stock the diameter of the Kool Stop pad insert section and reform the holder around it - close it up a tad. Grab a couple pairs of pads and be good for a lifetime. I also wouldn't hesitate to make the John Bull holders fit if I was confident it would work without mangling things. Who else is making replacement pads for them?
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What is missing for me is the measured dimension of the radius base of all pads shown. Are they the same or different?
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All I can say is that Kool Stop's rod brake pads fit my holders perfectly. They make great products. If multiple specs exist, and that seems so, they can't be expected to meet every one. Consistency of the British cycling industry being what it was. You can see tool marks on both ends where they were pinched in manufacturing.
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My speculation would be that the holders Kool Stop received and used for these reproductions might have been crimped more than normal. Thus leading to the undersized pads you received. Might there be a practical way to shim the pads as you insert them into the holders? Possibly, thin aluminum strips from a beverage can?
Thin strips from a beverage can won't cut it for the Humber. I didn't pay $24.95 for brake pads for a fit that's worse than the cheapest Indian repops money can buy. Ditto for the John Bulls, which - unlike the rod pads - are downright unusable.
All I can say is that Kool Stop's rod brake pads fit my holders perfectly. They make great products. If multiple specs exist, and that seems so, they can't be expected to meet every one. Consistency of the British cycling industry being what it was. You can see tool marks on both ends where they were pinched in manufacturing.
It's a method of making them work, but I dare say that there's a larger gap to the bottom of the pad here than it appears, due to the crimping.
-Kurt
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Rather than a metal shim, would bonding a layer of inner tube around the base be an option? Not that you should have to, just thinking of ways the part could be made right.
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