I have a 2002 Chevy S10 2 wheel drive with a wheel base of 4600. My factory tire size is 205/75/R15
Can I use a 235/70/R15 will there be any problems if I use this size?
Probably. I used 225/70 R15’s mounted on a set of Chevy Rally wheels on my 2001 S-10 with no problem. I may have just got lucky so make sure you check your clearances with the 235’s before you ruin a set of tires. P235/70R-15 all-season blackwall tires were standard on 4x4 models of your truck.
My experience with oversizing tires on older S-10s was discouraging. I installed 235x15s and they drug on the front fender liner on turns and even slight dips in the road. The larger diameter also changed the effective gear ratio and made overdrive unusable in normal highway driving without any gain in fuel mileage or performance.
@RodKnox…I had the same problem trying to put 15 inch wheels and tires on an '86 model S-10. I finally had to go with 14 Rally wheels. I had no problem with the effective gear ratio because the engine was a 350 (someone elses project).
I have no problem with upsizing tires that “fit” and have gear ratios that allow normal use. Even slight upsize may keep you from driving with loads if you have an already under powered motor. If you have 4 wd and low range and it fts, have at it. Other wise, be careful. It just isn’t worth it with under powered two wd trucks.
@missleman is right. There is very little change in final gear ratio of going to 225/70/ 15. I would feel quite at ease with this change on a small motor. I have upsized as much as could fit ( do test fits) with elevated 4 wd and v6 motors on either 2 or 4 wd. If you have a weak motor, you could be disappointed.
This seems like a pretty big jump in tire width, and I’d be concerned if such wide tires would fit properly on the current wheels? If you are planning to upgrade to wider rims then OK, but you might experience problems with rubbing on the frame or wheel wells.
If you use the car in areas where there is a lot of ice build up in the wheel wells during winter driving the bigger tires will make it worse.
Out of curiosity, why do you want to do this?
In addition to the possible problems already mentioned, you may find a greater tendency to hydroplane. Pickups are already light I the rear, so be careful in wet and/or slippery conditions on offramps until you know how well the new width will keep the rear end in line.
My daughter bought me the tires and didn’t check the “wheel base” but it all worked out,no problems. She surprised me and got them put on. There really isn’t that much difference except they are new 
Thanks for all the input this place is great
a 2002 Chevy S10 2 wheel drive with a wheel base of 4600.4600 what? millimeters?
bought me the tires and didn't check the "wheel base"Why would the "wheel base" even matter? Or am I just missing something?
Tire size might be different between trim levels but the wheelbase shouldn’t matter. Unless gm put a larger size tire on the Extended or Crew cab than on the Regular Cab with otherwise the same options. Your tire size is stock for a regular cab (Tire Rack doesn’t ask what wheelbase just which cab you have)