Ride height change with new tires?

[Nick D.]

Last winter I spooned on a set of Metzeler Sportec M-3s that are great, fast warm up, good turn-in, etc. These replaced a set of Sportec M-1s that I liked just as well. The problem is that now, on occasion I feel sort of a wandering feeling at high speeds in a straight line. Like I said, turn in is excellent in both directions, but on some roads the front end seems to swim.

I've checked the wheel alignment and all is well. Interestingly, the problem is greatly reduced now that I am sitting on a Sargent seat instead of the stocker. The Sargent has me sitting up much higher (almost uncomfortably so) which has me thinking that the height of the tires must have changed the ride height. Does this make sense or am I off base? I remember reading something similar in a tire comparo by Sport Rider magazine where they had ride height issues with their Michelins.

[Capt. Home Slice]

Tripple digit speeds? Tire pressure bad, front susp. too soft, profile of the tire like a wedge? These things will effect the feeling of the front when hauling the mail.

[BC51]

Originally Posted by Nick D.

Last winter I spooned on a set of Metzeler Sportec M-3s that are great, fast warm up, good turn-in, etc. These replaced a set of Sportec M-1s that I liked just as well. The problem is that now, on occasion I feel sort of a wandering feeling at high speeds in a straight line. Like I said, turn in is excellent in both directions, but on some roads the front end seems to swim.

A shorter front and a taller rear might contribute to what you're feeling but given the rake and trail numbers on the bikes you're riding I doubt it.

I vote tire pressures.

[Nick D.]

Originally Posted by Capt. Home Slice

Tripple digit speeds? Tire pressure bad, front susp. too soft, profile of the tire like a wedge? These things will effect the feeling of the front when hauling the mail.

Fast road speeds ranging from 70 - 90, tire pressure is fine and set to the spec on the frame sticker/owners manual, suspension has been revised to my weight. I'll check the air pressure again, but maybe it has to do with the tire profile. I'm not weaving all over the road, but you can definitely feel it, but it is only noticeable going in a straight line. I wonder if there is a combination of tire design and the crown on certain roads.

How would I go about checking for proper ride height?