when buying rotoflex rubber donuts, which brands should be avoided?


I see paddock stocks OE @155 pounds versus some other @ 20

Are QH crap in this context?

Cheers
Nick

ONLY ONE if you can find it

Metalastik* which is part of a Swedish concern now ??? Trelleborg?

There were TWO rotoflexes made by them...the NOS Triumph one available only from Triumph, and another almost identical but heavier duty one 21/932 which I have not seen in YONKS, and has no DISKS between the bolt fixing centres.....which you could buy from Metalastik.
The heavier duty ones were fantastic.

It's just as important to change the bolts at the same time as they break off with fatigue if you don't.

Don't even think about fitting anything else*, you will be transferred immediately to the ranting section  

Came across this some time ago: http://www.missionsupplyonline.com/pdf/rotoflex.pdf
Don't know how up to date it is. Looks like 21/979 might be the heavy duty one?

What is the expected lifespan from a pair of QH donuts. In case I cannot find proper ones? Should one just go for some kind of CV joints instead?



Cheers
Nick

WOW that is amazing!

How do you find this stuff??  

21/932 was the uprated one, and thanks to your excellent post I can see the original Triumph was 21/979 as you say with interleaved disks...oddly enough it's rated higher at 660 ft/lb and 440ft/lb for the other which had lower losses and lasted much longer.

In fact with the 4.55:1 axle and 200ftlb torque in 1st gear I easily see why it was WAAAAY over the limit ....

With a LSD over 1000ft/lb loading was giving so much deflection on the centres the bolts/squashed rubber were were rubbing on each other and polishing the forks!

The rotoflex bolts had to be changed every 3 months because all 12 used to bend!!!

....It seems I must have been putting 2700ft/lb loading on them,
......enough to spin both rear slicks on 8" rims, which even if you spread it over 2 axle shafts makes it a mental amount at 1300ft/lb per axle!!
FYI (Drive shaft torque = max eng torque x 1st gear ratio x axle ratio or 200x2.70x4.55...)

No wonder the UJs used to snap in half like pencils (QH again USELESS!)  ,- Unless you used genuine original Triumph HS ones.  

In fact with those figures in the table it gives 32ft/lb per degree deflection, so 1000ft/lb would give around 30 degrees deflection...certainly enough for the bolts to get close to touching and squash the rubber flat!

They don't give a max revs figure but I'm told it's 1200-1500max or about 80-100mph, we were taking them to an insane 135mph which is 2200rpm!  

SCARY!!

As for QH, I would give them about a week/1000 miles before they fall apart even on a STD car.

Most QH products don't have a lifespan as such, more like gambling, on your wordly goods each time you use the car.

if you use their doughnuts, I wouldn't stray far from home, perhaps 25 mile limit.

This is not an exaggeration.

L  

Unless you like wasting your money and changing rotoflexes (!) use only Metalastik (Trelleborg).  The others vary between crap and utter shite.  This is what drove me to the original CV joint conversion.  However if you can get the correct ones they do seem to last pretty well.

Nick

Edit: note that real ones have 'metalastik' moulded into them if they don't have this you are probably being ripped off (quite common I'm afraid)

OK, thanks. I will source the proper ones (even though the car is probably been put up for sale once resto is done - wife insist..... )

Cheers
Nick

Perhaps need to sell wife then....

Nick

While we are on the subject, the Hardy Spicer UJ's that Canley's sells as 'Heavy Duty' are from Land Rover Defender? They seem to be the strongest in that (relatively small) size.

For TR6 size, those made by Neapco seem to be the absolute best.

I have all the part numbers at home.

L

Quoted from lordleonusa

are from Land Rover Defender?

Freelander FWIW. Certainly the best available in that size.

There's "heavy duty" RHS152 which have a grease nipple & there's "very heavy duty racing" GUJ101HD these are the same as Land Rover Freelander propshaft UJs LR part no TVF100000 & don't have a grease nipple. I think the spec is the same but some say the grease hole weakens them.

I'd rather have a weaken joint with a hole I reckon...Only way I could get original joints to last was constant greasing.

Yes, I took your advice & fitted the greaseable ones this time. Lets hope they last longer than the last lot!