Talk Morgan Forums Morgan Sports Cars Morgan Three Wheeler & Super 3 Front Tire Feathering

I have 2,200 miles on the factory (I assume) alignment and the front tires are feathering heavily as well as showing some possible "depression wear" where some of the tread block appear lower/higher than others. Feathering can be felt when rubbing hand from bottom to top of tire in front of car.

As the second owner I don't know if the previous owner had the tires under inflated. I have been running 22 - 24 psi for the last 600 miles. Car tracks great at any speed. When pushing low speed corners it feels like the front end is scrubbing hard, and turn in isn't great, but this may be normal, not sure as a newbie owner?

I will say the wheels certainly lean with some visible Camber but I assume this is not adjustable?

I currently have no way to check Toe. I have never done it before, seems simple, just not sure how to do a good job without special tools? I have searched on posts but cant really find anything that walks me through it. Not really sure what the recommended setting is, I have seen 0 as well as 2?
Folks talk about mounting 2 bars high on the tire and measuring across them, but the body is in the way?

Thoughts about the cause of the tire wear and how best to easily and properly check toe??

Link to pic:

https://www.tm-img.com/images/2020/05/02/2020-05-02-12.05.01.jpg

I have used one of these: http://www.gunson.co.uk/product/G4008. and it works well with the M3W. I have set the tracking to 0 degrees and that seems to be good from a tyre wear and handling point, no tyre tread feathering. If you use the standard Avon SM tyres they do tend to feather and try to roll off the rim when pushed, they are not ideal. Blockleys or Excelsior tyres seem to be a better "traditional" option or there are several motorcycle tyres that give better performance but at the cost of very limited mileage. With Blockley tyres I have found that about 30 psi seems to be a reasonable compromise between ride and handling, although I have non standard shock absorbers that can be adjusted to compensate. The camber and caster angles are non adjustable with a standard set up, you can look at the Krazy Horse (Empire) suspension geometry correction kit if you want to optimise settings. It improves a bit on the now standard set up and vastly improved on the original pre 2014 suspension that the M3W came with then.

If you just Google setting front toe-in, you will see there are many ways people have come up with to measure toe. There is nothing special about the M3W when it comes to measuring or setting toe, other than the mudguards getting in the way. Many ideas on the proper value to use, but that's another story. Personally I set mine at 1/8" (+0, -1/32) (or 1/8" toe-in, as opposed to toe-out), and run my front tires (factory spec Avons) at 26-27psi.

As received (used) my machine had fairly massive (3/8") toe-out which made for very darty steering and feathered tires. There is a bit of a myth out there that these machines need toe-out, and I've no idea why that would be so. Moderate toe-out can be useful for track/racing cars to aid turn in, but in a street car you are looking for straight line stability and stability under braking both of which requires toe-in.

With the front mudguards removed you can do a quick (and somewhat crude) check with a tape measure and another person. With the steering straight ahead, and holding the tape as high as possible, and level, under the body work, measure the distance from the center of one tire to center of the other. Move to the front, and this is important, hold the tape at the same height above the ground as before and measure at the front. If the front measurement is less, you have toe-in equal to the difference in measurements. And if the front measurement is greater, you have toe-out.

BTW-while ideally you want to take these measurements at the mid point of the wheel height, for a street machine, taking measurements as high as practical will suffice. Just endeavor to take the front and rear measurements at the same height. s

The device I've been using for some years now to measure toe is this: https://tinyurl.com/toe-gauge

Hmm...I see they are a bit more expensive than they used to be, but what isn't. You can make something similar with surplus materials. In my youth my first homemade version was 2x2" lumber and coat hanger wire. Had to be very careful to not tweak the wires when moving from back to front! I later had a couple of versions of conduit based designs which served for many years before moving on to pro built alloy unit mentioned above.

I have a Guson Trakrite & they are easy to use, you need a short level clean area to roll the car. If you are going to use a measuring system on the tyre or wheel first spin the wheel to make sure the wheel is true & the tyre is centred. If not true you will get inconsistent readings.
I run my Blockleys at 26psi & rear Nokian Weatherproof at 28psi. I found the original Avons were wearing more in the centre at factory pressure.

Sounds like for a start I may want to try a few more PSI in the Avons.

That's great that the trackrite has worked for you guys. It sure seems simple and fast to use. I was not sure how it would do with the skinny tires of the 3W. Have you ever had the opportunity to compare the results with hard measurements?

I also like the idea of being able to take an actual measurement between the wheels. Thanks for the easy to understand explanation Bitsobrits! If you use one of those Toe tools like the one you recommended, do these type of tools take measurements off the outside of the tire or is it off the wheel? I also found one a bit cheaper on amazon. VKRP Toe Gauge

I noticed that this one seems to contact the tire, where the one you recommended https://tinyurl.com/toe-gauge uses a scribed like which seems far superior? I guess you have to jack up each wheel, spin and chalk before measuring, not a big deal.

I’ve been using these toe plates for M3W and they work great:

https://www.ebay.com/itm/331724195351

You can add a couple of sticky furniture felt pads at the back to measure of the actual rim.

BTW, I had a severe pull to the right from the factory, so had to upgrade the suspension with the Empire kit and dial in the castor/camber too.

Avons run much better at 28+ PSI.

Bluesman,

Planenut is correct you should verify the wheel/tire for trueness before embarking on any form of measurement. Any sort of scribe can work: chalk, Sharpie, even a screwdriver blade to make a viewable mark. Once I'm satisfied the tires are centered on the rim (i.e. the tread pattern isn't wobbling about-which is pretty rare) I no longer bother with the scribe and just measure off of the tread blocks themselves.

As for the cheaper one you found online, I did borrow one of those some year ago. The issue I found with indexing off of the tire sidewall is that raised lettering or any sort of sidewall embossed feature will affect the readings unless you can ensure contact front and rear with only a smooth part of the sidewall. And that design doesn't lend itself to indexing off the rim without modification. I politely returned it to it's owner and bought the one I use today.

Kankel's suggestion for toe plates is very valid as well, especially with our tall skinny tires.

As I do rebuilds and suspension setup on many types of cars I have found the pointer type that I use is the most versatile, allowing me to measure/set toe even without wheels present.

These look pretty easy to use. Do you have to take your mudguards off to use?

Nope, they do not interfere. I’ve glued a couple of round felt pads to the back (kinda like pointers) so I can measure of the actual rim and it works really well.

Repeating several points:

Avon tires will drive MUCH better at 27-28 PSI as well as last much longer.

They are rated for rear or sidecar use. Not steering.

Replace with Blockley or Coker Excelsior when they wear out.

O degrees toe in is optimal with the standard hardware.