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Big Fat Cow Syndrome. ?

M

Moretorque

Regular
Joined
Jun 20, 2025
Messages
382
Location
Florida
I am having Heifer problems, I never had this problem on MTB but with the Ebike and the excess speed when I go into corners it is tearing the stem out of tubes and the ride is unstable like the tires and tubes do not like dealing with 340 pounds going around corners at 25 MPH. Just wondering if I may need a fat tire bike or better yet cut the food off? I don't want a fat tire bike and would rather figure a way to make this work. thanks
 
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What PSI are you running?
You probably want a minimum of 75 PSI at your weight
Too little PSI and the tubes will slip inside the tires.. eventually breaking the tube > pressure valve connection.

To address the human part of the problem, i can't recommend a ketogenic diet enough.
 
I'll play around with it like I do, I run high pressure. I think I need to go buy a real bike. I think I am going to fast with my weight and the bike cannot handle it. It's like the whole back of the bike is moving around when I go into corners. 2 flats in 2 days and it's the valve stems being torn out at there base.
 
No , I bought one of the budget Actbest 27.5 class 3 bikes and I think I am asking to much of it. I don't think the frame is designed to handle my weight going that fast. The bike worked great going 20 but not pushing 25 to 30 MPH.
 
Is this the bike in question?
1775879896393.png


This looks like a middle strength frame, which is a bad idea for someone who needs something more heavy duty. I also see very narrow rims which these tires can definetely squirm on, moreso if the tire pressure is too low for the weight.

Bikes with no rear suspension start to feel rickety at ~25mph unless you intervene with an amazing seat post. Then you make it to 30-35 until it starts feeling rickety again.

What looks like a wimpy suspension fork which may even have a 1 inch headtube isn't helping.

You should build your own starting with a particularly strong mountain bike frame.
 
It's an ActBest Race model., the frame looks heavy duty. It seems like the back end is not made heavy enough. Are the fat tire bikes better if you are heavy? I don't want to spend a ton. I put Specialized tires on it 2.6, better tubes, 203 mm rotors, bar risers, 11/48 gearing and now going 25 to 28 MPH everywhere when I go around corners real fast on the street it feels like the entire back end of the bike is not strong enough. The bike says weight limit 350, the fat tire bikes are rated for 500 some of them but I do not want a pig bike. Maybe this hog should just go on a diet.
 
Wheels built for more weight have more spokes and double walled rims. Wheels built for tandem bicycles could definitely hold your weight. I don't think you need fat tires unless you want them. A steel frame would help also. I think Peter White builds wheels for tandem. Or you could build your own wheels.

The tire pressure you can run depends on the tire and what it is rated for and not the tube. Thicker tubes will help prevent flats.
 
I have not totally identified the problem, I just hit a corner going 25 plus and the rear noticeably moves around and sometimes the tire goes flat. The Specialized tires are way more heavy than the stock ones. The stock ones did this at 20 MPH.
 
Moretorque said:
No , I bought one of the budget Actbest 27.5 class 3 bikes and I think I am asking to much of it.
Click to expand...

Riding one of those crazy cheap and nasty mail order bikes is asking too much of it. Its only job was finished when you traded actual money for it. You can keep throwing money at it, but it will not turn into a good bike that way.

I thought you were pretty tall. What are you doing messing around with a one size bike?

You are right that you have not identified the problem. Even terrible tires will hold air and go around corners. I suspect faulty installation technique and maybe sharp edges on the valve holes in the rims. Those are only guesses because we do not have enough info yet to understand what is happening.
 
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Everything with the bikes is great but when I take corners going 25 or so something is not right in the rear, the tire I believe is trying to come off the rim and it tears the valve stem off. You go into a corner like that at 400 pounds total leaned over now think how that will try and peal the tire off. It also feels like the frame is moving around back there but figure 1 problem at a time.
 
Do you mean a gradual bend in the road or are you trying to take 90 degree corners at 25mph? If it is the latter, I don't think that it is a reasonable expectation for the tires to hold under those forces. Just slow down for the turn like the rest of us do.
 
Moretorque said:
I am having Heffer problems, I never had this problem on MTB but with the Ebike and the excess speed when I go into corners it is tearing the stem out of tubes and the ride is unstable like the tires and tubes do not like dealing with 340 pounds going around corners at 25 MPH. Just wondering if I may need a fat tire bike or better yet cut the food off? I don't want a fat tire bike and would rather figure a way to make this work. thanks
Click to expand...
What tires are you using and at what width?
 
RunForTheHills said:
Do you mean a gradual bend in the road or are you trying to take 90 degree corners at 25mph? If it is the latter, I don't think that it is a reasonable expectation for the tires to hold under those forces. Just slow down for the turn like the rest of us do.
Click to expand...
That's what I was wondering, Like I posted, I am coming off motorcycles so I am used to going alot faster than this. Will a fat tire bike be better about this. If I lost a 100 pounds I bet I would not have this problem or even 50.
 
Moretorque said:
That's what I was wondering, Like I posted, I am coming off motorcycles so I am used to going alot faster than this. Will a fat tire bike be better about this. If I lost a 100 pounds I bet I would not have this problem or even 50.
Click to expand...
Losing weight is a personal decision. I recently lost about 30 lbs and feel much better for it. Lots of other benefits from that too. My blood pressure is down and and I fit in some clothes that I haven't been able to wear in a few years. I was also told by my doctor that I am pre-diabetic and that number went down slightly this year. Although I am still borderline pre-diabetic.
 
Also, motorcycles are definitely built stronger than a bicycle. There are some tradeoffs with that. Motorcycles weight between 300-700lbs. Bicycles weigh 30-70lbs. Less than that for carbon road bikes and more than that for motorcycle like Sur-ons and the like.
 
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