I've never had the opportunity to do this and therefore can't answer the question, has anyone done a side by side mechanical comparison of a standard front caliper and a blue spot caliper, or are you aware of any physical differences that would make one better than the other (other than bridge flex).
Noel
What are you looking for Noel? Stopping distances? Brake pad areas? Fluid volumes? Piston sizes? Load deflection on a one piece body vs 2 piece split body?
Please elaborate.
Quote from: Pat Conlon on November 02, 2021, 12:08:23 PM
What are you looking for Noel? Stopping distances? Brake pad areas? Fluid volumes? Piston sizes? Load deflection on a one piece body vs 2 piece split body?
Please elaborate.
I get asked from time to time why folks change to blue spot calipers and I usually give some flippant reason and move on (I'm obliged to offer
some explanation because I also have them). I have just been asked yet again, but on this occasion by a new FJ owner who would like something a little more mechanical, hence my question. If there's a sound reason, he'll get some.
The question was why, excluding bridge flex, is it a commonly held view that blue spots are an upgrade.
C'mon guys, it doesn't have to be just Pat answering, everyone's got them.
Noel
Quote from: ribbert on November 03, 2021, 09:06:31 AM
Quote from: Pat Conlon on November 02, 2021, 12:08:23 PM
What are you looking for Noel? Stopping distances? Brake pad areas? Fluid volumes? Piston sizes? Load deflection on a one piece body vs 2 piece split body?
Please elaborate.
I get asked from time to time why folks change to blue spot calipers and I usually give some flippant reason and move on (I'm obliged to offer some explanation because I also have them). I have just been asked yet again, but on this occasion by a new FJ owner who would like something a little more mechanical, hence my question. If there's a sound reason, he'll get some.
The question was why, excluding bridge flex, is it a commonly held view that blue spots are an upgrade.
C'mon guys, it doesn't have to be just Pat answering, everyone's got them.
Noel
On my '84 when I upgraded to a 17" hoop the forks didn't include calipers, so it was an inexpensive route getting loaded calipers from e-bay. R1 calipers are a dime a doz and probably on average have less mileage than old FJ ones would have had. I was able to keep my SS lines because they had swivel ends.
On my '89 the clutch master needed a rebuild and I opted for a replacement master from an FJR. I 'upgraded' the brake master to match and calipers too. The calipers were from an FZ1 (silver plugs) and it was e-bay to the rescue again as I was able to get a complete sealed system including SS lines, calipers and master from the same bike at little cost. There was nothing wrong with the old system but I wanted things to match from the cockpit standpoint.
I was able to lock up the front wheel with the OEM setup on my '84 so braking power wasn't the reason for change and neither was weight savings if there is any. I do prefer the feel of this setup but I guess it came down to cost and aesthetics mostly.
Not technical, more hearsay, but I thought, I read somewhere that the two differing piston sizes allow for "better" brake modulation. I didn't get it straight from the horses mouth, so don't quote me on it.
You do have more pad surface area with the blue spots. I don't have both sets opened up. But looking at the pad area of the two sets in the packaging, the blue spot pads are about the same height but are about 1/2" longer for each pad.
Clamping force. We don't have a good way to measure that, here. Maybe someone else has the equipment to measure that.
Stopping distance. From what I have read on the forum, most adopters of blue spots report better stopping distance. But is that because of the placebo effect? Put an exhaust on, the bike is now louder, and now your making 15 more hp.. or at least because of the sound you feel like it is. Or is it the better tires?
If someone had the want. They could probably measure the deflection between the two with a dial indicator while someone grabs a handful.
I have no inclination to "upgrade" my brakes yet, but when I do, I would change to Stainless Steel braided hoses first. My present hydraulic hoses were replaced by the PO, several years ago, so they will last a good while longer. I may (later) change to the newer calipers and master cylinders, not because the older versions need much help, but just to make "rebuild" parts more available in the future for me. My 1985 is now over 35 years old, and finding new parts can be a hassle.
When I had the standard calipers I found the braking power weak, nearly rear ended a car one time with the missus on the back trying to stop, sure it'd lock the front wheel if you pulled the lever hard enough, but they always had a spongy feel to them as well no matter how many time they were bled. A rebuild may possibly have fixed them, but came across some blue spots cheap enough so fitted them instead. The difference was noticeable straight away, the bike pulled up way better and the lever had a firm but slightly wooden feel which was rectified later with a FJR master cylinder. Plus they look better than the standard calipers.
Calipers are just one part of the 5 part system. (rotors, pads, calipers, lines, m/c)
Just changing the calipers by themselves will result in little, if any, noticeable improvement. Changing the calipers, brake lines, master cylinder and brake pads together I saw a distinct improvement over my oem 1984 system.
Why monoblocks? Well, they were cheap. The monoblocks along with being structurally stiffer (less deflection, more stable, better load transfer to the fork legs) they employ what is called a differential bore design. Something my oem 2 piston calipers did not have.
Having 2 pistons of unequal size (per side) means that when the master cylinder pressurized the caliper, the 2 different pistons actuate at different rates (smaller piston first) this eliminates brake squeal (especially with sintered pads) and also allows the pads to wear more evenly. The larger piston exerts slightly greater clamping force to compensate for pad taper. The smaller piston is always located closest the the rotor entrance and the larger piston closest to the rotor exit.
(http://fjowners.com/gallery/10/49_02_02_17_11_23_22.jpeg)
Quote from: Pat Conlon on November 03, 2021, 02:54:46 PM
Calipers are just one part of the 5 part system. (rotors, pads, calipers, lines, m/c)
Just changing the calipers by themselves will result in little, if any, noticeable improvement. Changing the calipers, brake lines, master cylinder and brake pads together I saw a distinct improvement over my oem 1984 system.
Many moons ago (probably 1992 'ish) I switched to Goodrich stainless braided lines on my FJ. I was riding all the time with sport bike riders and felt my FJ needed more stopping power and less fade. I felt I got that with the Goodrich hose fitted, but with more ultimate stopping power came a much more "wooden" feel at the lever. I tried different pads, but nothing really made a difference.
When I was continually swapping my riding between our 2001 Fazer 1000 (FZ1) (even with its original rubber brake hoses) and my FJ, the difference in braking control and stopping power was staggering - I just felt so much more confident braking on the Fazer than I did on the FJ. That was when I decided to put the Blue Spot calipers and a Fazer 1000 (FZ1) master cylinder on my FJ - it just took a long time for me to do it (Blue Spots were very expensive in the early 2000's and second hand sets were extremely rare).
Luckily, as I'd swapped the forks/wheel too, I also upsized my rotors on the FJ to 320mm. Linking all this up with new stainless braised hose, stiffer front fork springs and an adjustable span brake lever (to get the most comfortable finger position on the lever) made my FJ's front brakes feel like night and day, compared to the original brake set-up.
Under heavy braking now, I feel as though I have much more control over the front wheel, with much better feedback from the brakes - which allows me to brake later and harder, where necessary, for corners - and in emergency stop practices, I rarely lock up the front wheel totally now, whereas I used to do it all the time - but I still manage to stop in generally much the same distance, maybe slightly shorter distances. I only practice from 10mph - 20mph in a car park, but I use the same parking space lines as my marker for applying the brakes as I did with the old set-up, so I have a good idea when I stop how well stopping distances compare and how much better the new brakes feel (from the lack of butt clenches from skidding the wheel).
All of this is empirical and subjective - but if it makes me feel better and more confident on the bike, then I'm good with that :good2:
Certain to say blue dots that replaced the sorry excuses for OEM calipers on my 86, pretty much halved braking distance. One of the cheapest and best mods made to date.
On the odd note of exhausts; Paul Lawson's lend of the OEM pipes gives a way more stealthy road presence, which had the following results on the test ride. Because my conscience knew I was significantly quieter, I felt I rode a bit nippier believing I had less chance of being heard by the cops. In addition, I couldn't hear my usual supertrapp wail, so didn't quiet know where I was in the rev range; another contributor to the pace running away a bit. I remember the article about the first time the racers got hold of the electric bikes and kept crashing them because the couldn't hear an engine noise. The tech boffins ended up installing speakers on the dash that made an electronic revving noise to help them out. Kinda like that playing card in the bicycle spokes idea.
Oh and furthermore, even though the OEM exhaust weighs a metric tonne, its low down and even on both sides, so I didn't really notice it. I think it breathes a little better with a 4 into 2, maybe. Do miss the off throttle pops though. Either way, its great to be back on the road again.
Andy
The original question was, comparing late model 4 piston calipers with blue spot calipers, both in good working order and excluding other improvements, does one have a mechanical advantage over the other?
Although the responses remain anecdotal, Pat and Robert are of the opinion that all things being equal, neither one offers noticeably better performance over the other.
You may recall a member here some years ago intentionally staggered the fitting of blue dots, HH pads, SS lines and smaller m/c entirely for the purpose of assessing the difference each part made by fitting them one at a time, it was also his observation that the caliper swap made no difference but as Tony (Bones) said, they look way better, I agree.
Robert, there's no need to check for flex with measuring instruments. If a caliper is flexing the pad material will wear in a tapered fashion, not something you see much of these days but it used to be common. I've run pads on both types of calipers down metal/paper thin and the wear is absolutely uniform suggesting neither type flexes even with very hard use, bikes don't operate under the same line pressure as cars do either so there is less force being applied.
Pat, if pressure continued to be applied (beyond max braking pressure) until spreading of the calipers was detected, there's a good chance it would be the mono blocks that deflected first. Steel is stronger and less heat affected.
Noel
Noel, this is true. I was thinking if someone wanted to be more scientific. They could get an actual number. By using some sort of pressure reading and a dial indicator. You could potentially measure X caliper deflects .002" at 60 psi of braking pressure and caliper Y deflected .009" at 60 psi.
I'm not interested, either way. If there were more hours in the day I might have time for such frivolous trials in regards to the calipers. We already know they work. As has been said, the biggest gain is in the whole package.
Chasing this tyke around takes up a good amount of my time as of late and I like to think it is time well spent. :smile:
It's never too early to begin training them
but didn't you start out driving go carts?
Running after them is definitely time well spent but if you have a couple more kids close together in a few years they will chase each other and you can just sit back watch and occasionally referee.
He has go karts already too. Just an opportune photo op with him in the race car. He likes to be by the race track in his stroller and takes off his ear muffs so he can fall asleep while listening to the roar of cars. After the race my wife jokingly told me, "I think his ears are broken. I took him up there with his ear muffs on, he took them off and fell asleep, right beside the track." :wacko3:
The main benefit I found from changing the whole system was brake feel and braking effort. I had the original set on the bike when I bought it. It was all stock bar braided lines. I found it took quite a significant amount of force to get the bike to slow and decelerate at a good rate. Also the brake feel at the lever wasn't great, it was better than my previous bike but also in comparison to the replaced system it wasn't great.
The new system which for me is a Fazer 1000 master with blue spot calipers, sintered EBC pads and I had to replace the lines as they were too short with a two line set from Venhill. I found there to be a lot more initial bite from the brakes and the effort required at the lever was significantly less. It took a slight squeeze on the new system to bring the bike to a halt which on the old setup would have required quite a bit more pull at the lever to achieve the same. Also the feel of the lever pull was a lot nicer in comparison to the previous setup, now it did take getting used to but I find it a lot nicer. The brake feel I will say is subjective but the braking effort as in how much you had to pull the lever there was a significant change.
I would have been interesting to do a test to compare how much shorter the brakedistance is on the 3 different setups.I mean old 2 piston and stock rotors, blue spots and late 4 pistons. (popcorn)
Quote from: Old Rider on November 08, 2021, 02:11:15 AM
I would have been interesting to do a test to compare how much shorter the brakedistance is on the 3 different setups.I mean old 2 piston and stock rotors, blue spots and late 4 pistons. (popcorn)
And then all 3 sets with braided hoses; and then blue spots with a matching master cylinder (FJR/FZ1) and then blue spots, matching master and 320mm discs; and then each set up with straight rate fork springs; and then with progressive springs.........
I feel a thesis coming on for some enterprising young engineering student into bikes :sarcastic:
Quote from: Old Rider on November 08, 2021, 02:11:15 AM
I would have been interesting to do a test to compare how much shorter the brakedistance is on the 3 different setups.I mean old 2 piston and stock rotors, blue spots and late 4 pistons. (popcorn)
Rolf, as has just been discussed there is no perceivable difference between the late model 4 piston calipers and the blue spots, one would expect the stopping distance to be the same (all things being equal)
Single and 2 piston calipers are generally not included in comparisons with modern calipers, there is no comparison. I can understand why owners upgrading from early 2 piston to later brakes are blown away by the improvement.
Noel
Quote from: f4fwildcat on November 07, 2021, 05:59:33 PM
The main benefit I found from changing the whole system was brake feel and braking effort......
Yes, the whole package not only improves the FJ's brakes significantly, but puts them in the company of modern bikes. I have a modern bike with 320mm rotors, big Brembo calipers, HH pads, partially integrated and servo assisted brakes, the harder I ride the more I prefer the FJ brakes, they are fantastic, it's all about feel.
Noel
Quote from: RPM - Robert on November 06, 2021, 08:36:53 AM
Chasing this tyke around takes up a good amount of my time as of late and I like to think it is time well spent. :smile:
Time with your kids is the best investment you can make, don't miss out, you blink and before you know it he'll be wanting to borrow the car for a hot date!
Noel