Front tyre wear - excessive? ST1300

[Duporth]

I have just fitted two new Michelin Road 5 GT tyres to my St1300. The Pilot 4 GT tyres removed had travelled 15,000km (~9,000 'ish miles). Interestingly, the front tyre showed more wear than the rear tyre. This was unexpected and seems very unusual.

Has anyone experienced a similar occurrence thanks?

D

 

[dduelin]

Not unusual with Michelins.

 

[SMSW]

Interestingly, the front tyre showed more wear than the rear tyre. This was unexpected and seems very unusual.
Has anyone experienced a similar occurrence thanks?

I wonder if a stye of riding would foster this kind of wear. Perhaps a lot of braking in curves, or some other technique? Or is the construction of a front tire significantly different than that of the rear tire?

 

[CYYJ]

...is the construction of a front tire significantly different than that of the rear tire?

I suspect construction of the two tires is very different, because they have very different demands put on them.

My experience with the PR4-GTs is that the front tire exhibits wear all around the circumference that comes in contact with the road - the rear tire only tends to show wear in the middle flat spot.

I am, however, very happy with the longevity of the PR4-GTs - I get almost double the mileage out of the PR4s on my ST 1300 than I do from the Metzelers on my ST 1100.

Michael

 

[Kevcules]

I've got a good feeling I'll get the same mileage out of my newly installed T31's ,as I've heard about the PR4's. The bridgestones are more than $100 cheaper.

 

[Catmandu2]

I generally get early wear on the front tires,,, which typically lasts about %75 of the rears. Softer compounds will only go about 2/3rd's of rears. I put it down to driving a heavy bike hard into corners,, and living near a bunch or roundabouts. Conversely,,, I only get about 2/3's the life out of my rear brake pads,, compared to my fronts. I put it down to the same causes as the unbalanced tire life. Riding a front tire with a harder silica compound,,, reasonable tread pattern for block stability,, and 42psi minimum will improve life. On the front I like the Metz Z8 HWM spec. cheers,, CAt'

 

[Duporth]

Thank you for many helpful and informative replies everyone. Much appreciated.
D

 

[SMSW]

I suspect construction of the two tires is very different, because they have very different demands put on them.

You are probably right. I have read that some mfrs warn against using a front tire on the rear (and v. v.) but that warning does not deter us from pushing the envelope. Adding a bit to the confusion when I was hunting for Guzzi tires, I found some that were rated for front and rear locations. My best guess would be bigger, heavier, more powerful bikes capable of well into the triple digits require more specialized tires than smaller ones, though I would think a 600lb Guzzi - even an older one - encroaches on that territory.

 

[dduelin]

Try Michelin Road 5s. They might change your opinion of Michelins. They did for me. I greatly disliked the vague feedback when pushed hard that the original Pilot Road, the PR 2 and 3 gave me, along with PR lumpy and odd wear patterns. I switched to Bridgestone after I got the chance to sample preproduction 023s for the US importer of Bridgestone. I was on a pair of Pilot Road 2s when Bridgestone came seeking real world data from heavy sport touring riders. My name came up through a business relationship of myself, the importer and US distributor. Bridgestone shipped a pair of 023s to me and paid for a shop to take off the PR2's and save them while I wore out the 023s. When the test was over and the PR2s were spooned back on I hated them. I went through the 023, 030, 030 Evo, and T31 years loving those tires on a ST1300. The RT I bought a year ago had Road 5s on it when I purchased it. Loved then and replaced with a second set, now a third new front as the fronts R5s wear faster than the rears under me. I had a pair of T31s on my previous RT and thought I'd never buy another Michelin. The T32 will have to be awesome to get off the Road 5s.

 

[Whooshka]

When was the last time you did a service to the front forks? I've been saying it for years but you'll be amazed what a flush, fresh fluid (7.5 wt.) and a 20 mm spacer will do to the ST's front end performance.

 

[CYYJ]

When was the last time you did a service to the front forks? I've been saying it for years but you'll be amazed what a flush, fresh fluid (7.5 wt.) and a 20 mm spacer will do to the ST's front end performance.

A very good point. I wouldn't go so far as to suggest modifying the front suspension system with a 20 mm spacer, but I do know from experience that simply overhauling the front forks - taking them apart, replacing worn bushings, cleaning everything out, and putting fresh fluid in makes a tremendous difference to ride quality. The front end performs much better, it actually absorbs bumps!

Whether or not this has any effect on tire wear I do not know, but a complete front fork overhaul yields a great improvement in riding pleasure. There's an illustrated "how-to" post explaining the process here: ST 1300 Front Fork Overhaul. The middle of winter is a great time to do this project, because if you are doing it for the first time and taking it nice and easy, it will occupy you for a couple of days.

Michael

 

[Whooshka]

I suggest the 20mm spacer because I and others believe the front is under sprung. The spacer stiffened it up just enough to eliminate the "bobbing" my front end used to do.

 

[dduelin]

Adding preload can't stiffen springs but it does increase the amount of weight required to initially compress the springs. In practice it raises the ride height by decreasing sag. I weigh less than most riders and only increased the spacers by 16 mm.

 

[dbst1300]

I wore out the front tire as fast as the rear when I owned an ST1300.....had to tell myself to slow down every once in a while....because the ST1300 weighed 725 lbs fueled up and was hard on tires if ridden in a sporting fashion.

 

[Duporth]

When was the last time you did a service to the front forks? I've been saying it for years but you'll be amazed what a flush, fresh fluid (7.5 wt.) and a 20 mm spacer will do to the ST's front end performance.

The forks and oil are as they came from the factory 2009.

 

[Whooshka]

Uh yeah....I'd change it out. Follow the link CYYJ posted above. It's not high tech. Just nuts and bolts. No need to swap out seals and stuff if you just want to flush and add new fluid. Some believe as long as you're in there might as well do seals but that will double the time and effort easily.

 

[CYYJ]

I suggest the 20mm spacer because I and others believe the front is under sprung.

Hi Whooshka:

I'm not criticizing the suggestion to add 20mm spacers - the message I intended to convey, and perhaps didn't articulate well enough, is that if it has been a long time since the front forks were overhauled, it might be best for an owner to just bring the front fork assembly back up to 'as new' performance by cleaning it all out and replacing (if necessary) the bushings & seals, and then evaluate their satisfaction with front end performance in OEM condition before making the decision to add spacers.

I do recommend that Duporth critically evaluate the condition of the four bushings (two per side) and replace them if necessary. They may or may not need replacement, it's very much an 'on condition' decision. Concerning the fork seals, though, I think it makes sense to replace them if they are 11 years old, primarily because they are rubber parts and they are not going to last forever. Maybe they might have another year or two of life in them now, but for sure they won't last another 11 years before they perish. So, to sum up, new bushings maybe, depending on condition, but new fork seals for sure.

@Duporth - if the front end has not been overhauled since new (11 years now), then for sure you will notice a considerable improvement if you overhaul it. The biggest difference I noticed was that the front end now absorbed bumps - all the stiction that was there before disappeared.

Michael

 

[Kevcules]

Clean fluid will help the shock function for sure. I changed my fluid at 40,000 kms as I wasn’t impressed with them. The shocks just rode up the bumps and didn’t absorb them.
Igofar said my bushings were probably still good with such little mileage and he was right. I changed them anyways as I had bought them and was already in there. No change after I assembled them.
What helped the most was checking and adjusting the front shock sag. Dduelin was right when he suggested I get 15mm longer spacers. At 170lbs without gear, my front end was down too low with me on the bike to give much useable spring left. This helped but what helped more was when I switched to a 5 weight fluid. Now I have better fluid motion up front.

 

[dduelin]

I did the first fork oil change at 30,000 miles and about every 15-18,000 after that. My preference was to mix two parts Honda 5 wt SS-7 with 1 part Honda SS-8 for a 6.7 weight fluid. I think it's [fluid degradation] something that changes so gradually you don't really notice a difference until you renew the fluids. I did the bushings and seals at 72,000 and they really didn't actually need it but at that point in my life I never had a bike I expected to keep to 100,000 miles or more and thought it was good preventative maintenance at what I thought at the time was 'high mileage'. That ST is over 200,000 miles now with the seals replaced at 72,000 still not leaking.

 

[Duporth]

An interesting point about 'riding style' raised by SMSW; I hadn't given it much thought as a factor, but around here riding is either motorway or hilly and twisty and I know the front end does some heavy work coming down the ranges, diving into tight turns, brakes...

I haven't previously taken much notice of front/back tyre wear and I always replace tyres as a pair. However, this time the wear on the front tyre, right across the width/circumference, was very noticeable. More wear than the rear.

I think the front end of my ST is in for a great deal of attention!

Thank you to everyone for help and knowledge. I have to thank Larry (Igofar) too, who has helped me on the subject.

D