upside down Mumford linkage?

[MaxRothery]

Is it possible to mount a mumford linkage upsidedown, above the axle as so theres not a problem with ground clearance

[TooMany2cvs]

MaxRothery said:

Is it possible to mount a mumford linkage upsidedown, above the axle as so theres not a problem with ground clearance

Never heard of it before, but looking at that article, the whole point seems to be to lower the roll centre. Putting it above the axle would have the opposite effect, wouldn't it?

[MaxRothery]

Was just wondering as I have ride night issues on my triumph as the speed bumps in my town are about 2-3 inches and the exhaust clamp bolts scrap with even a 1 inch drop. And I say about using it just mirrored above the axle as there is plenty of room above the axle

[v8250]

Yes, it is definitely possible to mount a Mumford above the rear axle and has been done many times. As note, the purpose of the Mumford linkage is, in fact, multi-purpose...providing excellent balanced live axle location, far better than panhard rod et al. Subject to correct rod length, linkage length and carefully planned mounting point location the roll centre and arc of movement will provide excellent mechanical stability to the back end keeping the driven rear wheels where they need to be...on the road/tarmac. One area to be careful of is the the rod lengths and having the rear suspension too stiff. It's also best to add fore/aft rod links to minimize axle yaw, but they must not compromise the Mumford linkage movement throughout its designed length.

[MaxRothery]

v8250 said:

Yes, it is definitely possible to mount a Mumford above the rear axle and has been done many times. As note, the purpose of the Mumford linkage is, in fact, multi-purpose...providing excellent balanced live axle location, far better than panhard rod et al. Subject to correct rod length, linkage length and carefully planned mounting point location the roll centre and arc of movement will provide excellent mechanical stability to the back end keeping the driven rear wheels where they need to be...on the road/tarmac. One area to be careful of is the the rod lengths and having the rear suspension too stiff. It's also best to add fore/aft rod links to minimize axle yaw, but they must not compromise the Mumford linkage movement throughout its designed length.

Thank you, the rear suspension is drop link and will be polybush when I'm done with it, that should be stiff enough to reduce axle yaw. I have rough dimension scales that I'll work on and see if that works

[v8250]

MaxRothery said:

Thank you, the rear suspension is drop link and will be polybush when I'm done with it, that should be stiff enough to reduce axle yaw. I have rough dimension scales that I'll work on and see if that works

Max, out of interest why a mumford linkage with drop links? Or do you mean rear trailing arms? Btw, what car is it?

[MaxRothery]

It's a triumph 1500 TC, and yeah, I mean trailing arms. After looking at some other linkages, it might be a satchells linkage in it but I'm looking to upgrade the suspension maybe

[v8250]

MaxRothery said:

It's a triumph 1500 TC, and yeah, I mean trailing arms. After looking at some other linkages, it might be a satchells linkage in it but I'm looking to upgrade the suspension maybe

The 1500TC has a dead beam axle, same as the Dolomite Sprint but without an ARB. I'd have thought a Mumford would be overkill for the 75bhp TC engine. Why not replace all the arm bushes, upgrade with adjustable coil-overs and add the Dolomite Sprint's ARB. It's all been done before...you'd be best contacting the Dolomite Club and having a chat with them as they'd know the precise components that work well for the body/chassis.

[MaxRothery]

v8250 said:

The 1500TC has a dead beam axle, same as the Dolomite Sprint but without an ARB. I'd have thought a Mumford would be overkill for the 75bhp TC engine. Why not replace all the arm bushes, upgrade with adjustable coil-overs and add the Dolomite Sprint's ARB. It's all been done before.

It would be overkill for the 1.5 but I'm planning to throw a lot more horses under the hood and I want to be safe in the knowledge that I've got plenty of grip and I'm not going to roll over at the ride height I want it at

[v8250]

MaxRothery said:

It would be overkill for the 1.5 but I'm planning to throw a lot more horses under the hood and I want to be safe in the knowledge that I've got plenty of grip and I'm not going to roll over at the ride height I want it at

Okay, that makes sense. As a point of ref' I'm in the process of completing a TVR V8 conversion into an MGB Roadster with 250bhp. The back end is now IRS through a Cosworth Viscous LSD with adjustable coil-overs all round. Yes, slightly different to your FWD & rear beam axle. How much extra power/which engine are you using...noting the FWD set up.

[MaxRothery]

v8250 said:

Okay, that makes sense. As a point of ref' I'm in the process of completing a TVR V8 conversion into an MGB Roadster with 250bhp. The back end is now IRS through a Cosworth Viscous LSD with adjustable coil-overs all round. Yes, slightly different to your FWD & rear beam axle. How much extra power/which engine are you using...noting the FWD set up.

I'm looking to put somewhere in the region of 220 bhp with the use of a supercharged MX5 1.8 and it's the RWD variant so all the power is being sent rearward sand maybe if I can rework the front spindles, I might be tempted to go AWD in the future with a North/south set up but that's way way way in the future

[TooMany2cvs]

v8250 said:

Yes, slightly different to your FWD & rear beam axle. How much extra power/which engine are you using...noting the FWD set up.

Triumph 1500 was the long nose/long tail version of the FWD 1300.
Triumph 1500TC was the RWD Dolomite-bar-the-badge. They looked identical from the outside...

...only the British motor industry...

[MaxRothery]

And, I think you could get a RWD 1300 that's also a long nose and tail and the only denoting features between 1300, 1500, 1500TC, and 1850 was badges... Only BMC

[TooMany2cvs]

MaxRothery said:

And, I think you could get a RWD 1300 that's also a long nose and tail

The Toledo 1300 had the short tail and a simplified version of the Dolomite nose, then it became the Dolomite 1300, with the simpler nose but the long tail.

[Mr2Mike]

v8250 said:

Yes, it is definitely possible to mount a Mumford above the rear axle and has been done many times. As note, the purpose of the Mumford linkage is, in fact, multi-purpose...providing excellent balanced live axle location, far better than panhard rod et al. Subject to correct rod length, linkage length and carefully planned mounting point location the roll centre and arc of movement will provide excellent mechanical stability to the back end keeping the driven rear wheels where they need to be...

The roll centre of a mumford linkage is the (virtual) point at which the two outer arms intersect. If you mount the linkage above the axle, then the ends of the outer arms will have to be mounted way above the axle to maintain a reasonable roll centre height. If you don't/can't do this then the Mumford linkage has no benefit over a watts linkage.

[MaxRothery]

Mr2Mike said:

v8250 said:

Yes, it is definitely possible to mount a Mumford above the rear axle and has been done many times. As note, the purpose of the Mumford linkage is, in fact, multi-purpose...providing excellent balanced live axle location, far better than panhard rod et al. Subject to correct rod length, linkage length and carefully planned mounting point location the roll centre and arc of movement will provide excellent mechanical stability to the back end keeping the driven rear wheels where they need to be...

The roll centre of a mumford linkage is the (virtual) point at which the two outer arms intersect. If you mount the linkage above the axle, then the ends of the outer arms will have to be mounted way above the axle to maintain a reasonable roll centre height. If you don't/can't do this then the Mumford linkage has no benefit over a watts linkage.

Thanks Mike, I didn't know how the roll centre is located with a Mumford linkage, I see what you mean by it's not very good to mount it above the axle, I'll look more into it and see what I'll be able to do