Coah

Question: Trying to figure out why i feel rock solid /stable on the my e-mountain bike but my acoustic mountain bike feels unstable as hell. Even on slight grade gravel the acoustic tire is spinning out and feels like it wants to slide out the sides. on my ebike and i feel rock solid and stable.

I want to rotate in a non-ebike and also get into some longer rides that my ebike can't make, but what the heck. I test road the stumpjumper and the salsa cut-throat and those seemed to feel more stable but I didn't test them on gravel. Is it possible I just don't like the top fuel. What attributes do you think would influence the stability other than the weight. Would less kobby tires help?

I should also mention i have clip ins on the Trek which i now believe was moronic for my skill level but I have a road bike background.

Backstory:
Hey i'm a 36 year old dad, with only casual experience mountain biking but I live outside Boulder, Co, and have plenty of local trails I'd like to be able to do. The trails i want are more cross country touring (green rating) rolling hills and some badlands traversing. I'm not of fan of ripping downhill.

Currently i have a Trek top fuel Mountain bike from 2020. Forget the options level but i spent about 4600 on it. ~24 lbs - has 2.4 inch maxum knobby tires

I also have a ebike : Cannondale neo tesoro X speed which is built on a mountain bike frame. 58 lbs - has 2.4inch hybrid city tires (Big bens)

prj71

e-bike is heavier...better traction.

Could also be differences in geometry between the acoustic and e-bike.

Ironfish653

Weight could be one thing; technique and set-up also plays a big part.

An uneven pedal stroke (stomping or "mashing") can cause the rear wheel to break traction; could be that the E-assist is smoothing out the power delivery, giving you the appearance of better technique.

Set-up could be effecting it, too; too high of a tire pressure can decrease traction; lower pressure allows more of the tread to interact with the road surface.
Could also be that your MTB tires are too aggressive; I don't know exactly which Maxxis tires you've got, but something like the Minion DH has much larger, more widely spaced knobs, designed for digging into soft, loose surfaces, than say a hardpack XC tire like a Conti Race King, which has smaller, more closely spaced tread, putting more rubber in contact with the trail surface.

The Top Fuel is full suspension; the rear shock could be set too soft for your weight or riding style. If you're not used to rear suspension, and your shocks are too soft, it can definitely feel like the back wheel is moving all over the place, because it is.

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Coah

RE: Ironfish

Thanks for mentioning the rear shock. I just pumped up the front before this weekends ride, it was definately too low but I didn't do the back yet. I used a friends hardtail trek the other day and it also felt more secure so that jives.

tungsten

acoustic? it's a meatcycle!

letrebici

What sizes are both bikes?

The weight alone is a major factor in stability.

Headtube angle and wheelbase!
Trek Fuels are more XC oriented so the head tube angle could be much steeper than the Tesoro. Priority on quick handling means you have more direct input. Longer wheelbases are much more stable. Almost every E-bike has a longer wheelbase than an equivalent meatcycle / acoustic bike.

letrebici

checking out the geometry comparison at Bike insights. the Bottom Bracket height is much lower on the Top Fuel as well. so the Cannondale e bike will have a lower Center of gravity. But at more than double the weight of the very lightweight Top Fuel.

things you can do to make the TF more stable... increase your stem length by 10mm. as others have mentioned make sure your suspension air set up (SAG) is set for your weight. and then tweak from there. slightly beefier tires. slightly wider and heavier. helps with damping the vibrations. But also check the rebound settings on both the fork and shock if set incorrectly. it can be like a pogo stick.

I have a 24lb hardtail and a full suspension trail bike and the stability difference is very noticeable. So, to me, the geometry (longer wheelbase) and tires are the main factors. they are within 3.5lbs of each other. I am a 57 yr old trail rider not a shredder. so I need all the help I can get. So, I am a fan of stability over wild handling ability.

john m flores 

Are you going uphill or downhill in this situation? Is the feeling of sliding out on the front tire, rear tire, or both?