Roller Bearing Bell Cranks - RBBC's

[ross]

Do you reckon there's much thrust forces acting the bearings MC?

Cheers, Ross.

[coxm]

I'd have to look at one and think about it - and don't have one handy any more!  I can't believe that Simon would spec a much, much more expensive and complicated bearing unless he needed to, though.

MC

[dingo]

Engineering input comment from Brammo staff on why there is not true thrust bearing on the Brammo RBBC:

"The problem is that there is no good way to seal the thrust bearing without adding "stiction" to the system. 

Which is why we chose to run IGUS thrust washers on both sides. 
IGUS manufactures materials specifically for thrust applications, they are low friction, relatively low cost, and offer a long term reliable solution. 
With these washers properly lubricated they add very little "stiction" to the system but still have the same end result as a true thrust bearing".

(sic) -Time will tell.

[dazzas-atom300]

I know this hasn't been commented on for a while, but i was discusing this with the wifes dad and him being the traditional old school trained engineer advised on lubing the PBBC I have for now...
I gave me some rather expensive ptfe oil, gave them oiling and i can say that makes a big difference... possibly not as good as RBBC's but certainly well worth a go...
Not sure on the make of the ptfe lube, i'll ask him but it was engineering stuff... gutted also as he took one look at the bell crank and said "Mmmm could have knocked that up at work no problem with sealed bearings..." he's a real propellerhead, mad as a hatter but very clever with engineering stuff... pitty he's retired could have had mine for peanuts...
Daz

[Bruce Fielding]

I made mine at home with an aubergine...

[coxm]

Daz,

They aren't either difficult or expensive to fabricate. Its the bearings that are expensive.  I have the part number somewhere if you want to get the out law to knock a set up.

PBBCs will work better if lubed.  Same as most parts of a car - they aren't fit and forget.  Maybe best not to lube the brakes of course (save for a bit of copper grease in the right places.

MC

[sportyking]

Shortly after taking delivery of my 2nd hand Atom from the factory the rear PBBCs began to squeak.  On investigation the grease was in a right state so I asked Simon whether or not it would be a reasonable solution to fit grease nipples.  He never said it was a bad idea but did say they only needed lubing once a year (not excessive use) to keep in good order, so I am going to test this out over the next season.  If I have no issues through the summer I will just strip and re-grease next winter but otherwise I will fit the grease nipples.  The only downside I see to well placed grease nipples is the that the PB bushes really need channels in them for the grease to move around and push the old stuff out.  The plus is that a squirt of grease could be done in five minutes at a track day.

After this season I will consider the merits of the RBBCs against the cost, which just seems to much for me at present.  A guy at Plans Motorsport told me that an Atom shod with A048s is two seconds quicker than other track tyres on their track, so, I bought the Toyo R888s and saved myself £170 while also keeping this and PBBCs as in my back pocket as excuses for being so slow

[coxm]

I think you need to lube PBBCs more than once a season.  We changed Puff's to RBBCs after a couple of months and there was already significant scoring in the PBBCs that came off.  A grease nipple isn't a bad idea at all, but its clear from having seen inside a few of these that you need to get the dirt out.  Maybe plenty of grease going from the centre of the bearing to the outside would clean them and stop dirt getting in.  Don't know.

As an aside, I assume that the factory had lubed the PBBCs before delivery, so if they start squeaking soon after that, I rest my point.

MC

[RichardR]

Having had a car with standard BC and now RBBC, I can't begin to explain how much better they are. There is zero crashing apart from the very nastiest potholes, and it can actually be driven hard down bumpy lanes without threatening to jump into a hedge. It rides smoother than the Exige I recently had, and more in line with a sports saloon. As a result the whol;e car feels more 'finished' and higher quality.

IMO if the choice was between RBBC or the next engine spec up, I'd get the RBBC every time. In fact I'd choose them over any other option.

[Atom120]

[quote="sportyking"]
A guy at Plans Motorsport told me that an Atom shod with A048s is two seconds quicker than other track tyres on their track
[/quote]

All depends what the "other track tyres" were!! If they were ACB10s, and there was a 2 second difference, it'd have been the other way round!!

[jon b]

[quote="RichardR"]

Having had a car with standard BC and now RBBC, I can't begin to explain how much better they are. There is zero crashing apart from the very nastiest potholes, and it can actually be driven hard down bumpy lanes without threatening to jump into a hedge. It rides smoother than the Exige I recently had, and more in line with a sports saloon. As a result the whol;e car feels more 'finished' and higher quality.

IMO if the choice was between RBBC or the next engine spec up, I'd get the RBBC every time. In fact I'd choose them over any other option.
[/quote]

You don't get a better endorsement than that!

How are you finding the whole car Richard - obviously happy with the suspension - how about the rest of the car?!

[RichardR]

Hi Jon


Rest of the car is mainly great. There's lots of detail changes from my '04 220 that make things better. IMO though the frog-eye light situation is just crazy - need some proper dual HID projectors.

245 is much more torquey than the 220 I had (or maybe it's the cold air).  The other day in the damp, the rears lit up in 4th at around 70mph under hard acceleration. Really can't see myself being able to get the extra power of a 300 down in this weather. Falken tyres may have something to do with things though.

Whilst the RBBC ride much better, I can't really judge them on the handling improvements in these conditions. Initially I thought the car felt a bit 'bobby' and not razor sharp. After a few miles, I think it's just plushness, and again the ridiculously treaded Falken tyres probably arn't helping, also I've had the shocks set 1 from softest. The 220 I had 2 from softest on the rear 1 from hardest on the front.

Few niggles:

-Gear linkage keeps coming undone. Luckily my uncle was out with me when it went first time, he showed how to manually put it in gear to get home. Still had to get home down the motorway stuck in 3rd yesterday when it went again -sounded painful (60mph @ 8krpm). Factory will sort in the next few weeks.

-SS exhaust finish is already half peeled off

Can't wait to get it on track.

oh...and I got a cat too 

Richard

[jon b]

Thats good to know - have to say i'm not wheel spinning in 4th or if i am i'm not feeling it with the 048's

What is going on with the exhaust - that is just crap - i can't remember how much the polished finish was - but it wasn't cheap

They have to go to stainless steel - as least as an option - i'll be speaking to tom on this again soon

How did you get it in 1st if you lost the linkage?

Cheers
Jon B

[Bruce Fielding]

[quote="jon b"]
How did you get it in 1st if you lost the linkage?

Cheers
Jon B
[/quote]

Step 1 - crawl under car.
Step 2 - pop it back on.
Step 3- tie it up with zip ties from your tool kit in the boot.

It's not difficult and it won't happen if it's adjusted properly. This adjustment is usually done at the first service, but occasionally it pops off before that. It's an easy fix, but annoying, nevertheless.

[jon b]

Bruce - is it a good idea to put cable ties on anyway to stop it dropping off or assist from not coming loose?