16 replies to this topic

[TimS]

I have just come to try to fitting my rose jointed bottom arms from mini sport and have found that the pin that nromally holds the rubber buses on for the bottom arm is a too large diameter for the internal diameter of the joint. Has any oen had this problem b4? will I have to get the diameter machined down? il have pics 2moz as soon as im back at uni

[Woody]

rose joints not realy suitable for road use (unless you do very low milage ) as they wear very quickly .

[Jammy]

What sort of characteristics would you get from worn rose joints?! My steering feels quite light recently, kind of like I'm on wet/icy roads. Might be that my tyres have not got much grip left!

[Guess-Works.com]

Just a thought, but are you sure you have got the metal sleeves off the pin which will use to have been part of the bushes...

They have a very common habbit of rusting themselves to the arm. The only way I've found to remove them is to put the arm in a vice, and heat the end where the bushes were until the outer is red hot, you will see the sleeve heat first, allow to cool slightly and with mole grips, woblle left and right, eventually they will loosen and can be withdrawn..

[dklawson]

Good point about the sleeves. They do tend to stick in place. Shock bushings tend to do the same thing.

Rose joints will take all the compliant motion out of the suspension. (There are no elements left with any "give"). All those nice squishy rubber and hard plastic bits you're used to are gone. The suspension will feel very precise. It will also transfer every bump and shock into the car. As mentioned, they really aren't for a street car.

[Jammy]

Is it possible to say roughly how quickly they will wear, maybe compared to normal joints?! I use my car everyday and probably do about 100 miles a week.

[dklawson]

I don't think there's a way to predict the life of a rose joint. They are typically open and dry. The harder you drive, the more you drive in wet weather or dusty/dirty conditions the quicker they'll wear. Perhaps someone who uses them on the track will enter their comments and share their experiences.

[MiniMoi]

Yes I heard that the rose joints are unfit for road use too. But what about those titanium bottom arms that Force Racing sell. They look adjustable to me.

http://basic1.easily...mbottomarms.htm

MiniMoi

[dklawson]

The arms are adjustable for length, but you can't adjust out the wear in the joint itself.

For those who have never seen a rose joint or other spherical bearing, imagine a steel ball, now machine two equally sized flats at two parallel spots across the diameter of the sphere. Drill a hole through it, right on center, from one flat to the other. Now take the ball and put it inside a short hollow cylinder. Squish the cylinder down until it buckles, trapping the ball inside. That's your rose joint.

When they wear, you have a ball floating around loose in a bigger spherical cavity. They literally are made by swaging the outer race to the ball and them machining the deformed outer ring. There's no way to adjust the play out once they're worn. The only acception I've seen to this is a spherical bearing product called a Lufa bearing where the ball is removable and replaceable.

[neil_g]

im fitting roses to my project but im fitting seals to, hopefully, increase life.

minispares sell seals for £7 each

[TimS]

cheers guys! they much b stuck on, i though this might b it as the spacers that they sent are the same diameter! rose joints can be used on the raod and are used in some high performance cars, though i understand that bearings will easily wear when exposed to the elements so they will be protected by some home made sleeves. and the car wont b used everyday! its a bit of a project while im at uni iv got the fiat cinq for an everyday car.... horrible

[dklawson]

I've never seen sealed spherical bearings. What you may want to try is taking the dome shaped rubber seals that come with the Mini ball joint kits and putting one on each side of the joint when you install the rose joint arms. Pack those full of heavy grease and they may offer some lubrication and protection for the bearings. However, you could just as easily trap road grit and turn the grease into lapping compound.

[TimS]

im modiying a bike innertube to stop dirt from earinging them out, though the grade of metal used on the bearings must be pritty hard and they are replacable too. thanx for you help guys!

[neil_g]

im going to pack the seal with grease and then close up all the openings.. so hopefully a longer lasting rose

[TimS]

just taken a pic of mine, sorry for the poor quality, taken on my phone!