What will it take to convert a 2.0 to accommodate 4” tires? Post links if you got them!

Bujee1

New Member
Region
USA
I’m tired of hunting for Hi performance 3” tires when there are so many 4” tires available. I have 2.0 that I want to mod to accommodate 4” road tires. I need some advice. I know I need to change my fork, but to which one? And will I need to swap out the wheels as well?
 
You might be able to just get tires. Bike tire size width is just an estimate based on what RIM width the MFG of the tire feels the rim width that would be optimal for the tire design. The important size is the 20". Just because you buy a 4" wide tire doesn't mean it will be 4" wide on the rim you put it on. The wider the rim, will be the wider the tire. If your fork has just under 4" width the narrower rim you have may make for a taller and narrower 4" tire. Having said that, the rims might be too narrow. I have a 1.0 so don't have ability to measure the 2.0. It's a little difficult without calipers to measure rim and fork width but do your best to get close and post that here. Close measurements will likely be close enough to give you better guidance.
 
You might be able to just get tires. Bike tire size width is just an estimate based on what RIM width the MFG of the tire feels the rim width that would be optimal for the tire design. The important size is the 20". Just because you buy a 4" wide tire doesn't mean it will be 4" wide on the rim you put it on. The wider the rim, will be the wider the tire. If your fork has just under 4" width the narrower rim you have may make for a taller and narrower 4" tire. Having said that, the rims might be too narrow. I have a 1.0 so don't have ability to measure the 2.0. It's a little difficult without calipers to measure rim and fork width but do your best to get close and post that here. Close measurements will likely be close enough to give you better guidance.
I have a 1.0 as well as a 2.0. I’ll take measurements. Good call!
 
You might be able to just get tires. Bike tire size width is just an estimate based on what RIM width the MFG of the tire feels the rim width that would be optimal for the tire design. The important size is the 20". Just because you buy a 4" wide tire doesn't mean it will be 4" wide on the rim you put it on. The wider the rim, will be the wider the tire. If your fork has just under 4" width the narrower rim you have may make for a taller and narrower 4" tire. Having said that, the rims might be too narrow. I have a 1.0 so don't have ability to measure the 2.0. It's a little difficult without calipers to measure rim and fork width but do your best to get close and post that here. Close measurements will likely be close enough to give you better guidance.
1.0 wheel 88.9 mm, 2.0 , 76.2 mm or 3.5 in vs 3.0 in for folks in ‘Merica.
 
It will take a frame that allows a tire that wide. It's simple to measure.
I know the stock front fork will not accommodate the fatter tire and the rear will work if I remove the fender. Johnnie Rocket gave me great advice to measure the 1.0 wheel and compare to a 2.0 wheel. The 1.0 wheel is a half inch wider. That means if I mount a 4” tire on the 2.0, the tire will be taller and narrower than stock. So, to get the same look and ride I will have to get a new fork AND get my wheels rebuilt with 3.5 inch hoops!
 
You might be able to just get tires. Bike tire size width is just an estimate based on what RIM width the MFG of the tire feels the rim width that would be optimal for the tire design. The important size is the 20". Just because you buy a 4" wide tire doesn't mean it will be 4" wide on the rim you put it on. The wider the rim, will be the wider the tire. If your fork has just under 4" width the narrower rim you have may make for a taller and narrower 4" tire. Having said that, the rims might be too narrow. I have a 1.0 so don't have ability to measure the 2.0. It's a little difficult without calipers to measure rim and fork width but do your best to get close and post that here. Close measurements will likely be close enough to give you better guidance.
So I found some road tires at REI.They are 20x 4.5. You were right, the narrower rim made for a more narrow footprint. It fit just fine in the back but jus barely rubbed the fork in the front. I took a dremel to the inside of the fork to give me another millimeter of clearance. I like the look and will probably try the wider fork next.
 

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So I found some road tires at REI.They are 20x 4.5. You were right, the narrower rim made for a more narrow footprint. It fit just fine in the back but jus barely rubbed the fork in the front. I took a dremel to the inside of the fork to give me another millimeter of clearance. I like the look and will probably try the wider fork next.
So it seems like if you could have stayed with a 20x4 instead of the 4.5" it would have just barely fit without any other modifications? While riding and turning hard the tire will flex laterally and more so on a narrower rim than wider. That lateral flex might rub on the fork without 2-3mm clearance. The MTB community is known to really push the limits on tire width clearance YouTuber Berm Peak and KevCentral come to mind. Berm Peak actually took a grinder to the edge of his tire knobbies to make one set fit on one of his builds.
 
I’m tired of hunting for Hi performance 3” tires when there are so many 4” tires available. I have 2.0 that I want to mod to accommodate 4” road tires. I need some advice. I know I need to change my fork, but to which one? And will I need to swap out the wheels as well?
So if your front fork is too narrow for the tire you purchased then either switch to a slightly narrower tire or...... Replace front fork, front axle (because the drop out will be wider) add the correct width spacer to the axle. The front wheel bearings are loose ball cup and cone so you will need to watch some YouTube videos on how to do that and the front fork tube cut to proper length (more YouTube videos). Amazon or AliExpress search for "Fat tire front (suspension?) fork". If you're doing front suspension then more decisions such as amount of travel, air or oil etc....
 
I would put the Kenda K-Rad or CST Big Boat road tires available from Rad Ebikes one is a 3" the other is 3.3" road/multi use. So much easier than replacement of fork, axle etc
 
Those tires are on backwards.

Also as you roll down the road that tire is going to bob and weave a little within the fork, not just at ground level. Thats not enough clearance to keep it from rubbing the fork. The end result will be a groove worn into your tire sidewall that, under the wrong circumstances, can cause the tire to split at speed after it wears a deep enough groove. Its a kind of common problem with fat tire forks that are 4.0" compatible and people try and run 4.5-4.9" tires on anyway. I get away with it by running the front tire at low pressure which is enough to make the difference.
 
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