Many people think that the larger the wheel the more weight it should support. However, this is a false fact. Talking to any engineer they will tell you that smaller wheels are able to support larger weights.
As on November 2019 Neil Campbell currently holds the fastest land speed record on a bicycle clocking a speed of 174.339mph. In which he uses 20” wheels due to the overall strength.
However, without customizing a bike not many manufactures make adult bikes with such small wheels. Therefore, for people looking for bikes for heavy people.
We would recommend going for a 26Inch wheel over a 29Inch purely down to the technical facts of the bracing angle on a 26 inch wheel is far better and can support more weight.
Number of Spokes
When it comes to the number of spokes you should look for. Many standard bikes will come with 24 or 26 spokes.
The problem with this is for heavier people wheels with fewer spokes will end up breaking the wheels due to the fact that fewer spokes make the wheel less durable and ultimately cannot support heavier weights.
It is recommended to try find a wheel with as many spokes as possible. Any user over 200 lbs. I would recommend at least 32 spokes.
Although these cost more, ultimately the wheel will be durable enough to support your weight.
Quite often than not most bikes out of the box will come with standard tires which hold around 60 PSI. I would always recommend for users to switch out tires to a more heavy duty tire.
Although this has the added cost it would defiantly be worth it if you plan on using the bike on a regular basis.
Tires such as the Schwalbe Marathon which has a higher maximum PSI of around 100 would be able to support heavier users compared to standard tires which would have a maximum tire PSI of around 60.
95% of bikes out of the factory will come with a standard narrow seat. This would be uncomfortable for heavier users. It would be a recommendation that you look for a wider seat that consists of a memory foam layer.
Not only would this help distribute the weight over a larger area. It would also make the riding more comfortable.