poor handling at top speed

"The front tire wants to shutter and the whole bike feels like it is wiggling"

You will want to check your wheels, one of them may be slighty bent,if it is you can true it so it will be straighter. I know cause this happened to me before. Also check your brakes and make sure a brake shoe is not rubbing a wheel causeing a wheel to be pushed over.

Out of balance?

I agree

From your description it does sound like the dreaded "tank slapper" - the "wiggling" bit in particular. Caused by out of true and/or balance wheels I've not yet had a problem with it on my bicycles, but remember it ...fondly... from my motorcycles. With the limited speed/weight of an MB I dunno if it'd be the same - but on a motorcycle the symptoms are pretty constant, if the wobbling starts at say 80mph, it'll always start at 80 - it'll get worse if you go faster - but won't stop till you drop down to 60mph or so, depends on variables - but it's always a lot less than the starting point.

The only other thing I can think of is tracking, your front and rear wheel's alignment with each other and the bike...

I would bet it's the slime tubes, my wheels aren't balanced on my rides & I've no problems - but I'm not runnin' the goop. I imagine it's prolly variable, if ya goop the tubes and ride immediately for a while mebbe it spreads it out more uniformly than if ya goop 'em and let it sit?

I dunno... I thought about the slime stuff... but then was horrified by the mental imagery of a blow-out and the resultant mess, so I put it back on the shelf heh. I've really not had a problem with flats ever since I got good tubes & tires *shrug*

I'd run w/o goo and see before I got into "balancing" bicycle wheels, motorcycle rims use clip on weights and/or stick-ons BTW

Looks like it was Tom that did the solder trick

http://motorbicycling.com/f3/wheel-balancing-slime-5438.html

I agree. Slime can be a nightmare for balance at higher speeds. Though, I have seen some that was made for motorcycles! I guess I would put it in the tire if I had a flat, just to get me home but that's about it.

Must be the slime.

I run Extra thick "Flat Proof" Bell tubes that have sealant in them and my bike will top out @ 38MPH and has NO wiggle or wobble and no wheel balancing has been done on mine.
So this is a ????

I say just to cover all points I would go with non slimed tubes and see if it makes a difference, it does sound like a out of balance problem of some sort.
Hope you get it figured out soon, good luck.

and there is no play in the suspention fork slides.....

I don't use the paper thin preslimed tubes. I use thick heavy duty thorn proof tubes with lots of slime in them. A little More than the directions state to use like to think I have a little side wall protection. I have used this stuff with thick tubes for over 20 years. Never have I ever had a problem with tires being out of balance at high speed, If I had a jumbolia reflector on the wheel I had always took those off. My thought was they would loosen the spokes where they were mounted to. To this day I will brag that they balance a wheel.

Whats more is the paper thin preslimed tubes in my experience come with a minuscule amount of slime in them.[Not going to balance a tire] Also a paper thin tube is a racers deal for cutting corners on weight in my opinion. A pin hole in a paper thin tube is very unforgiving for any stop leak. Uber speeds on a Motored Bicycle I go with a thick tube! I found slime works really well with a thick Heavy Duty tube...

Some folks live where there is very little road hazards , Sickers cacti etc. Not where I live!

These work on the same principal.

Centramatic Tire Balancers

Slime is heavy. If you have really good kevlar tires please try a decent set of normal bike shop tubes. Not Walmart, not super hvy duty either. They make the tire get way hotter at speed on the road and they are heavy. You only need hvy tubes for trail riding thorns or to make up for cheap tires. I run servas drifter S tires with standard tubes. They have 5 layers of flat protection and inverse tread. Use good rim strips. I have zero flat problems. You want to keep the spinning weight at a bare minimum if you want to go fast. I have no balancing weights and standard weight spokes on good rims and hubs. If you have good quality wheels they are too light and well made to need balancing. At over 20mph about 30% of your HP is being used spinning the spokes thru the air. Fat spokes equals slower speed. Look at a Olympics Bike, that's why they have 3 wide thin spokes. If your not jumping rocks good quality spokes in the standard size are fine if you have a shift kit or one of Jim's Hub Adapters so your not torquing the spokes themselves. I use a $25 3/32 drive chain with riveted pins for the shift kit. Standard shimano hub/cluster. If you look at a Walmart bike rear hub closely you will see the bearing on the cluster side is set nearly in the middle of the hub. Shimano hubs run the bearing close to the outside. It's spreads out the support on the axel. Whether you like shimano or not they are a much stronger hub for a reasonable price. Dishing the wheel for a cluster has nothing to do with it as long as the spokes are tight and right. My bike will run with mods including shift kit,CNS carb,tuned pipe,slant head,opti-2 oil/75 to 1, at 42mph in a calm wind on a dead flat 4 lane road. That's clocked by 2 different cars not by a bike speedo. I ride a steel GT triple triangle frame just like yours. Broke a costco bike frame last year. I have no suspension at either end not because I wouldn't like it. Adding a suspension fork to a bike that didn't come with one, esp if it's a long travel fork is dangerous. Bikes with no suspension have less fork angle than a frame built for a suspension front end. As the suspension colapses the angle gets less and less. I promise it's the slime unless your new fork is a suspension fork and the frame isn't made for one. It sounds like you have done everything else right. It will cost you less than 20 bucks to prove I'm right or wrong. I weigh 220lbs. I have over 2500 miles on my bike including the rebuild.



I'm not trying to ruffle any feathers. I'm just saying what works for me. I do Zero offroad.

Why are tubes thick for ATV's and car tires? My goodness they should be overheating! Slime is worth its weight in gold it balances a tire and helps prevent flats! That weight disperses. At slow speed can't ever be felt at high speed can't ever be felt. My bike 80 pounds me 240 , cargo up to 40 pounds. I got 15,000 miles on the motored bike thing. 60,000 plus miles pedaling.

I try to run 26x2.7 tires on all my bikes there as smooth as you can get one , and yeah that's a lot of slime. Oh yeah I don't cut corners in weight on my pedaling bikes they all get the same recipe. Need pictures? My pedal bikes are full sus down hill bikes retrofitted to touring gears 52 tooth front sprocket always rain or shine.... I use 135mm bottom bracket , Tripple Trap Pedals , and Tripple Crowned 700mm travel plus forks. 6 foot 11 inches I am.... I do zero off road myself.


My testing and tried true deal was avoiding road bikes and any thin tires I don't like the bumps in the road beating me up or the handling. 26x1.75 tires down are two rough for me and I they don't hold traction to my liking. A tire that will sponge a little will hold a road. Down hill world cup tires steal bead for my rides! I do enjoy the exercise!

So point being I run heavy tubes, great big honking tires with zero balancing issues.

The only tank slapping I do is gettyup!