Cycling costs

I've already posted real data on how much it costs to run a car, or to be more precise, the costs based on a statistical sample of 1 car, motoring_costs.htm now lets see how much it costs to run a mountain bike.  I bought a new bike for commuting exactly 12 months ago and I've logged every journey made and every penny spent on it.  I therefore have very good data on how much it costs to run a bike.

Cost per mile

Data is  presented on the basis of actual cost and depreciated cost.  The actual cost is simply the sum of everything I spent.  This is OK over a long time but if you were to spend £400 today on a bike, ride it back 1 mile from the bike shop, the cost would be £400/mile, i.e. it doesn't take into account the life of the component.  I therefore assigned a life to non-consumables and the depreciated cost is the fraction of the purchase cost based upon its current age.  If a component cost £300 and I assigned a life expectancy of 3 years then the depreciated cost would be £0 on day 1, £100 after 1 year, and £300 after three or more years.

So after 12 months, here are the data.

i.e. it cost me 23.47 p/mile to run a mountain bike over a 12 month period and covering 3114 miles.  If a meteorite was to hit the bike and destroy it, then the cost would increase to 48 p/mile.

I know this is not  a politically correct thing to say, but it can be cheaper to run a car (~20p/mile) than it is to run a mountain bike.  That's not based on any assumptions or anything, its based on my own actual data.

Cost breakdown

Here is a breakdown of the costs and the assigned life of components.

You might think that £110 for a helmet is excessive but I do like light weight and comfort.  This is in any case balanced by what's not in the list: tools, existing clothing, existing lubricants and service items.  Also, I had a really nice set of wheels from my old bike which I transferred to this bike, no cost appears for this (nor does a credit for the cheap and nasty wheels the bike came with).  You'll also see quite a few service items in there, chains, sprockets, bearings etc. take quite a hammering, I fully expect to have to buy another new set of chains and sprockets in the next month or so. 

The costs are further reduced as I do all my own maintenance.  This is a non-trivial task.  The chain needs stripping off the bike, degreasing and re-lubricating preferably every week but as a minimum every two weeks - mud, sand and oil make an excellent grinding paste.

Longevity

How long do parts last?

I've now replaced the groupset (chain, rear cassette and front and middle chain rings) twice .  The first time round the Shimano chain snapped at 1550 miles and a new chain spun on the worn sprockets so these had to be replaced as well.  The Shimano chain was never cleaned properly, just oiled every week as its not possible to remove the chain without driving a rivet out.  I replaced the chain with a SRAM 971 (£20) which has a split link which allows you to take the chain off easily.  This chain lasted 2025 miles before it started spinning on the cogs.  However, at least every two weeks the chain was removed from the bike, put in a bath of degreaser, cleaned and then oiled.  This tender loving care extended its life by 500 miles or 33%.  A complete groupset cost £116 and lasts 2000 miles, so that's equivalent to 5.8 p/mile just for chains and sprockets.

At 2000 miles the SRAM chain had stretched 4%.  Its recommended to replace chains at 1% stretch.  Assuming wear is linear (I'll check it on the next chain) then if you don't want to replace all the sprockets when the chain finally wears out then you'll need to replace the chain every 500 miles.  SRAM PC951 chains cost £15 so it would cost an extra £45 in chains to replace them at 1% stretch.  Would the sprockets last more than 4 chains?  Don't know is the answer to that one.  The sums show that the sprockets would have to last at least 8 chains or 4000 miles to make replacing the chain at 1% stretch cost effective.

The forks on my bike (Suntour XCR) now seem to have more play in their bushes than in the suspension movement.  This is after 3500 miles.  The suspension movement is most definitely no-where near as smooth as it was when they were new.  I'm guessing the forks will need to be replaced at about 4000 miles.

Headset bearings.  Cane Creek cheap and nasty bearings were fitted to the bike.  They were stripped down and greased twice during their life, before they finally gave up the ghost at 3500 miles.  It cost a whopping £3 for new bearings. :o)

Endura  MT500 overshoes.  What a waste of money (£20) these were.  The zips are seriously poor quality and broke after only 4 uses.

Truvativ Isoflow bottom bracket lasted 800 miles before it started creaking and at 1300 miles it was creaking so badly it was driving me nuts and I replaced it.  The replacement Shimano XT bottom bracket (with hollowtech cranks) has lasted 2200 miles so far and is still going strong.

The Shimano Deore front derailure was replaced at 2040 miles as it rattled so badly it was gouging the crank arms.  It was replaced by the Deore LX bottom bracket which after 1500 miles shows no sign of rattling.  Note that the Deore LX bottom bracket comes in top pull and bottom pull configurations.  I have the bottom pull on my commute bike and the top pull on my weekend fun bike. The bottom pull is fundamentally flawed in that it allows dirt and grit to collect in it which jams it all up.  The top pull variant doesn't suffer like this.

Rear derailure.  The Shimano XT rear derailure is still going fine after 3500 miles.

Spend profile per month

Mileage profile per month

Non-commuting (e.g. going to the shops) miles per month

Note that the big jump in May 07 was when I raced this hardtail bike against my full suspension bike to see which was faster. See  hard tail or bouncer comparison page (click for link)

 Cost versus miles