Achillesbulk

Hey gang, I am sure you get these sorts of posts all the time - but I could use some assistance.

First: A general stupid question regarding tire pressure. My current bike's tires say between 40-65 PSI, though I admit getting them any higher than 40 with my pump seems to be a huge chore. What are the dangers/problems to over/underinlfating tires? Give my size (250 lbs) would being a little under or over be preferred?

I currently ride a 1999 Diamondback Sorrento Mountain Bike, 18 inch frame 21 speed. I've been ready to get a new cycle, and I promised myself the next time I had to spend money on the bike, I would look at getting a new cycle, and that time has come as I blew a tube a couple days ago.

I am 6'1, 250 lbs. I ride 3-5 times a week, between 30-60 minutes a ride. I basically do neighborhood riding on streets, with the occasional cut through a park or small dirt trail. I don't do any actual mountain biking at this point, I am riding for fitness/pleasure. (I've lost about 90 lbs in the last couple of years)

Based on my planned usage, my LBS guru suggested a hybrid, and pointed me toward the Trek Verve 2. However, I am not sure I need the suspension, so I was considering the Trek Verve 1 and the Trek Shift 1. (Links below)

Verve 1 - Trek Bicycle
Shift 1 - Trek Bicycle

I like the styling of the Shift better than the Verve, though I suspect the tired of the Verve are probably more conducive to my cycling goals. The Shift is 7 speed Vs the Verve's 21 speed. I find myself rarely using anything by 15-21 gears on my current bike as is.

Could I get recommendations from the community between these two bikes, or does anyone feel I should get the suspension and go with the Verve 2 (or Shift 2)?

I appreciate your thoughts, thanks in advance!

Retro Grouch 

The biggest problem with under inflated tires is pinch flats. If your tires don't have enough air pressure you can pinch the inner tube between the rim and a pot hole, bump or curb and create 2 parallel slits that make your tube look like it was bitten by a snake.

I used to think that more air pressure was better but it turns out the physics don't work that way. An over inflated tire doesn't roll any better and rides much more harshly.

At 250 lbs I think you'll be best off with your tires inflated near their 65 psi upper limit.

I didn't examine the specs in detail but I suspect the 21 speed verve will give you a wider gear range than the 7 speed shift. If you never ride challenging hills, however, you may never feel the need to access those additional high and hill climb gears.

dynaryder

Sounds like you need a new pump. My first floor pump was a el-cheapo Rav-X;it wouldn't go over 85psi. Replaced it with a decent Performance house brand and no issues. As RG said,at your weight you'll want to run them fully up.

As for the bikes,ride both and see which you like best. If where you live is flat,and you don't use all the gears on your current bike,then the shift may be best. If you have hills,and/or use most of your bike's gears,then you'd want the Verve. Also note that adding a triple or double to the front of the Shift will be relatively costly compared to just getting the Verve in the first place. If you don't have any serious back or wrist issues,I wouldn't bother with front suspension. Both bikes you linked to have steel forks and wide tires.

cyclist2000

Are you trying to fill the tires with a frame pump. Get a good floor pump to pump the tires before each ride. I have a silica and a park tool pump. They both will get up to the 65 psi, I inflate my tires to 95-105 psi.

BlazingPedals

Neither of those two bikes are any better than what you already have. Get some new tires and tubes, and a new floor pump. Since you don't ride much off-road, see about some road-type tires in a 26x1.5" size. Pump the tires up to their max pressure so you don't bottom them out. If your current bike has issues, you can have a lot of repairs done for $400.

John Redcorn

Going 65 from 40 you should notice some easier pedaling too. I know I did when I made almost exact same psi adjustment on MTB.

nfmisso

So other than the bike you have is WAY too small for you; why do you want to DOWNGRADE your ride?

I am 5'10", standard leg/torso/arm length, and on the street ride 21" to 23" older MTB framed bikes, with the seat raised quite a bit above the frame. An unscrupulous bike shop (Hyland on Meridian in San Jose) sold me an 18" frame Raleigh Venture, it was extremely uncomfortable due to not enough leg extension even with the seat post all the way up. If they had sold me a 21" or 22" model, I would not have become thoroughly pissed and might not have taken the effort to learn a lot about bicycles......

Avoid suspension. It is a major detriment on the street and even for light off roading.

It looks like the Diamondback Sorrento model went to crap after the 2000 model year, the last year for the cro-mo frame. 2001 was hi-ten with front suspension (uck!) and 2002 was aluminum with front suspension (even worse).

You want to get your current tires up around 60-70 psi. A few psi over will not hurt; a few psi lower is actually more damaging due to excessive deformation of the tires' sidewalls.

Pumps: Zefal Air Max Floor Pump, White: Outdoor Sports : Walmart.com I have one these that I keep at work, which everyone borrows.... It is used for everything from low pressure MTB (40-50 psi) to high pressure road (120-130 psi) tires. Everyone who uses has commented very favorably on its speed and capacity, and really like the easy to read dial gauge.

VegasTriker

+1 to the advice that your current bike is too small by several inches. I ride an 18" frame and I am much shorter than you. Your current bike sold for $260 brand new so it isn't a great bike but the Shimano drive train components are two steps above what you will get on the new Trek bikes for twice that price. Take the money and look for a larger sized used bike with better components.