Spring perches: Roller vs Brass

[Rusty67]

A friend of mine ownes a frame and alignment shop and has recently started making his own spring perches. He uses brass bushings instead of the roller bearings but he was telling me that he has a new center shaft custom made that is bigger then the stock one for upgraded strength.

Today I came across the upgrade that Opentracker has been doing with the roller perches when I was reading the post about drag racing. Since then I've been going back through the archives and read up on a lot of his other stuff. I havn't really seen anyone talk about the brass ones much but I did see them mentioned and pictured on another website.

I guess the question is.... which one is better ? I would imagine that a quality sealed roller bearing would work better then a brass bushing because it would yeald a greater over all reduction from friction ? Altho I suppose that a brass bushing basically would make the spring perch a non-wear part ? What about the increased size of the center shaft ? That could be done with a roller bearing as well I suppose, does that aid or hinder performance ?

 

[danny clemens]

Another site that I frequent just had a discussion on this. They concurred that the roller bearing perch was only good for drag racing and would not hold up the the stress of every day driving.

 

[jerry S]

Another site that I frequent just had a discussion on this. They concurred that the roller bearing perch was only good for drag racing and would not hold up the the stress of every day driving.

If the roller spring perch is only good for drag racing, then why did OpenTracker make and install one on his open track car? that makes no sense whatsoever.

 

[Jester67]

Another site that I frequent just had a discussion on this. They concurred that the roller bearing perch was only good for drag racing and would not hold up the the stress of every day driving.

What site? I would like to visit it and see their point of view as I see it these would be a great addition to any front-end upgrade for a streetcar.

 

[LMan]

Another site that I frequent just had a discussion on this. They concurred that the roller bearing perch was only good for drag racing and would not hold up the the stress of every day driving.

 

[Pathfinder65]

I've made a set of both. I first made the bronze bushing ones

and then replaced them with the roller perches.

Handling wise I didn't notice a difference. What I did notice was that the bronze ones tended to groan after a while and needed lubrication. Perhaps I made them with too little tolerance? I don't know but I wanted to make the roller ones anyway. I really don't see them as too weak for street driving. Mine have been on for almost 10,000 miles of abusive driving and they were inspected at the end of last summer. No signs of losing it and just as free rolling as the day I made them.
The bronze perches I made are now on a track car and the driver loves them.
I guess it's whatever you prefer.

Dave

 

[Opentracker]

I had the same question when I made my first set. That's why I have been testing roller bearing perches for the past two years on street cars, road racers and drag racers. The oldest set on the street has 30K+ miles on them. Some of the road racers are in thier second season with no problems. The drag racers aren't having any problems either. I wanted a true roller perch so I used sealed roller bearings rather than the bronze bushing. Till we do more testing to find out how long the roller bearing perches last, I don't know how you could say one is better than the other. The bronze bushing perch has been around since the early 60's. The roller bearing perch is just a few years old. I know a few of us have switched from bronze perches to roller bearing perches to get away from the greasing/rebuilding the bronze perch requires. The bearings in the roller perches can be changed also if needed.

John

 

[10secgoal]

I don't understand how they could come to the conclusion that the bearing wouldn't last. seeing as all four tires use bearings to attach themselves to the vehicle.

 

[danny clemens]

What site? I would like to visit it and see their point of view as I see it these would be a great addition to any front-end upgrade for a streetcar.

The site is www.mercurycougar.net go to Classic Cougar Tech

I didn't say which ones were the best. I don't know. I'm just passing info that I think came from knowledgeable people

 

[Rusty67]

Hmm.... so far it seems like there is no performance difference between the two ?

What about upgrading the center shaft size, good idea ? Does it even mater ?

 

[bnickel]

Hmm.... so far it seems like there is no performance difference between the two ?

What about upgrading the center shaft size, good idea ? Does it even mater ?

i would say the center shaft size doesn't really matter much, especially on the roller bearing type. it might help the wear characteristics of the bronze bushing type due to the longer arc it would create but i doubt it would help much. i have a set of Opentrackers roller perches and they are very well made, i too was comsidering going with the bronze bushed ones at one point but decided the roller bearing version would need a lot less maintenance since they are a sealed unit. basically you'd just drive on them until the bearings wear out then replace the bearings and keep on going. even if you had to change the bearings every 25-30,000 miles they would last about forever on a limited use car and even a DD would get a lot of use out of them, besides even a high quality timken bearing is fairly cheap for this application, a complete set of 4 would probably be less than 50 bucks, cheaper than a repro set of spring perches.

 

[Pathfinder65]

Hmm.... so far it seems like there is no performance difference between the two ?

What about upgrading the center shaft size, good idea ? Does it even mater ?

I pressed a sleeve over the original shaft. Not so much out of a concern of re-enforcing the shaft but it was much easier to ensure that a smooth surface was pivoting on the bronze. I think the original shaft is strong enough but I didn't want to lathe grooves in the shaft for the c clips and perhaps weaken them. The grooves were cut into the new sleeve. If you look at the pic you can see the sleeve over the shaft

I suppose it also gives more of a surface to pivot on as well.

Dave

 

[Hack]

I see roller bearings as by far superior to a brass bushing in every way (edit: other than for really cheap mass produced equipment that doesn't need to be high quality. Bushings can be really good to help meet a low price point.)

If the bearings are spec'ed out for the proper load, they should never fail. I agree with the wheel bearing analogy. The nice thing about the spring perch is that it isn't spinning at high rpm, so the bearing should last much longer than a wheel bearing.

Look at any rolling application. What is used in a cheap assembly, and what is used in an expensive one? Remember the changes made to the T5 when they made it world class?

What do they use to support the shafts in rotating assemblies in big power plants? How about spindles in high accuracy CNC machines?

But if you buy some cheap POS equipment, you'll get the bronze bushings.

Can you tell my mind is made up?

 

[mustangbrad]

I am not an advocate for either bushings or bearings. I just want to point out that these comparisions to spindle bearings may not be quite accurate. Think about how a bearing works on a spindle, the inner or outer race is typically moving one dirrection around the other thousands of times. In the case of roller perches the inner and outer races will never move more than a few degrees its whole life, and this small movement is what drastically shortens the life of the bearing. It has been my experience that if there is less than 180 degrees of movement a bushing will last much longer. One final thought, think about the cam, rod, and main "bearings" inside your motor. They are really bushings and they can last for years at several thousand RPM's. Again I am not advocating the use of one over the other, because either is a drastic imporvement over stock.

 

[1320stang]

Well, the cam and crankshaft don't ride on the bearings, they ride on a thin film of oil, or are supposed to.

I've never had a roller pilot bearing on a manual tranny, but I've had several bushings that were wallered out and some that came out in pieces.

To me, it would seem the opposite, that a bearing that only had a few degrees of movement would last longer as it's supported all the way around, whereas the bushing would tend to wear on one side. I recently replaced rear axle shaft bushings on my rear engine Snapper, they were wore thru to the outer edge of the bushing, they were starting to wear on the sleeve the bushings fit into.

 

[mustangbrad]

Well, the cam and crankshaft don't ride on the bearings, they ride on a thin film of oil, or are supposed to.

I've never had a roller pilot bearing on a manual tranny, but I've had several bushings that were wallered out and some that came out in pieces.

To me, it would seem the opposite, that a bearing that only had a few degrees of movement would last longer as it's supported all the way around, whereas the bushing would tend to wear on one side. I recently replaced rear axle shaft bushings on my rear engine Snapper, they were wore thru to the outer edge of the bushing, they were starting to wear on the sleeve the bushings fit into.

What causes a bearing to wear prematurely in a small movement situation like roller perches is a tiny contact patch between the roller and the race. Roller bearings are designed to go round and round for a long time so a different roller surface is introduced to the race all the time. Not back and forth in tiny incriments with the same two surfaces constantly coming into contact. A bushing should be making contact on the entire length of the shaft. So the bushing will wear on one side like you said, but so will the bearing. But if you over-engineer the bearing assembly it should last a sufficient amount of time, especially on a vehicle that is only driven on weekends or at the track.

 

[Rusty67]

So it would seem that a properly selected bearing will work better then a bronze bushing in terms of longevity and there is no real difference in performance ?

 

[1320stang]

I agree that it will wear, but with the bearing being a sealed unit, with clean steel and oil/grease and no contaminates, it would seem that it would wear much more slowly than a (oil impregnated?)bronze bushing that is exposed to the elements and is inheriantly a softer material than steel.

The bushings I've seen are only contacting the shaft in about the same locations as the bearings. Now if your talking about a sleeve with a full bushing the length of the sleeve, I can see it being a little more equal.

 

[Red5oh]

What causes a bearing to wear prematurely in a small movement situation like roller perches is a tiny contact patch between the roller and the race. Roller bearings are designed to go round and round for a long time so a different roller surface is introduced to the race all the time. Not back and forth in tiny incriments with the same two surfaces constantly coming into contact. A bushing should be making contact on the entire length of the shaft. So the bushing will wear on one side like you said, but so will the bearing. But if you over-engineer the bearing assembly it should last a sufficient amount of time, especially on a vehicle that is only driven on weekends or at the track.

Just another thought on this... what about needle bearings? You get many more of them, they are longer, but the only problem, are they sealed like the roller versions?

 

[Jester67]

Just another thought on this... what about needle bearings? You get many more of them, they are longer, but the only problem, are they sealed like the roller versions?

I have been looking at Tapered roller bearings compared to roller bearings they have better characteristic for this application but I have not been able to find what I have been looking for but I am getting very close

Tapered Roller Bearing Set
Loads: Dynamic lbf: 6180, Static lbf: 6970
R142RS
Loads: Dynamic lbf: 1735, Static lbf: 1110