Posted by Les Faber in I am “trolling” for a new bike. I already have a great Hybrid bicycle – Trek 7.5 FX. It’s a great machine for short or long rides. But I need (want) a road bike so I can go out and really burn it up.
With any (potential) purchase comes research….. as you cannot simply go and out and buy a bike without making sure you are both compatible. Kinda like buying shoes that are either too big or too small for you. They look great at the store. But when you get home and try them on…..
So here are some hints (that I have used) to make sure that me (you) and my (your) future ride are 100% compatible.
Step 1: Talk to your other half and let them know that you are looking at getting a new (or another) bike! This is not obligatory – but clearly recommended.
Step 2: (Really step 1): Measure your inseam. This is best done barefoot. Stand against the wall and put a book (or something similar) between you legs so it pressed right up against your pelvic bone. Make a mark with a pencil on the wall along the top of the book. Measure the distance from the floor to the mark in centimeters. NB: This is for a Road or Hybrid bike. Mountain Bike (similar) instructions are below (Step 4).
Step 3: Use your inseam measurement to get a rough idea of your road bike size. Multiply your inseam by .65. This will give you a good estimate of your road bike size for bikes measured center to center. Thus if your inseam is 78 cm, you will fit a 51cm road bike (78 x .65 = 50.7). Some road bikes are measured center to top. To determine how to fit these bikes, multiply your inseam by .67 instead. Get it? Make sure you understand the difference when you get out and do some shopping. A good bike shop will know this bit of trivia.
Step 4: This is for Mountain Bikes – Subtract an additional 10cm and convert this measurement to inches to get your mountain bike frame size, roughly. Thus, if you fit a 51cm road bike (center to center), you will fit a 41cm – or a 16 inch – mountain bike.
Step 5: Do not forget to take into consideration the length of the bike’s top tube (seat to handle bars). This is probably more important then your inseam as you can adjust vertical height more easily (by raising / lowering your seat) versus horizontal sizes. In other words a road bike that has a 51 centimeter frame size may have a longer / shorter top tube. To complicate thing even more, most bicycles are designed for the male anatomy (long torso / short legs) versus the female anatomy (long legs / short torso). I know, who ever notices?!?!?
Step 6: You have done the math…. like the color…. agreed on budget, etc…. Take the potential bike for a spin. And, there is nothing wrong with showing up at a bike shop decked out in your best Tour de France garb. Don’t worry Spandex is cool – No really it is! You have to feel physically comfortable on your ride. A good bike shop will have no issue at all with setting you up properly on a potential ride as they know that if you are happy you will turn over your hard-earned money to get the ride you want. Plus they have a reputation to uphold.
Step 7: If you have omitted Step 1 (above), go home and beg for forgiveness. You just got a new bike!
looking to purchase a TREK 7.5 FX. Have you made your decision on a new bike…are you going to be looking to sell your 7.5? If so, what size, how much? Thanks.
Hi Dan – You misunderstood inasmuch as I am looking to buy a second bike – not sell the Trek and replace it. The Trek has proven to be a great all-round ride and I would recommend it highly (so would Helen who has the exact same bike). Sorry if you were misled by my post – L