Sep 1, 2012

Balloon tyres... (Schwalbe Marathon Supreme 26 x 2.0 folding tyres review)

I have recently fitted a set of large volume (balloon) tyres, a set of Schwalbe Marathon Supreme 26 x 2.0 folding tyres.

They replace my worn out set of Continental City Ride 26 x 1.5

The City Ride tyres were not great tyres at all: uncomfortable at high inflation pressures (70 psi), vague and slow at lower inflation pressures (40 psi), dreadful in the wet since new, with little traction on anything other than clean tarmac, and suffered greatly in lower temperatures (below 8 Celsius.)

But, they were cheap, and as far as puncture protection goes, they were very reliable: only one puncture in 12,000 miles. The rate of wear has been really great, probably explaining their reduced grip in cold and wet weather conditions.

Although the Marathon Supreme comes in both 1.6 and 2 inches wide models, I chose to try the 2 inches wide model on my commuter bike, and try a 'balloon' tyre for a change.

I am so far, pleased with my choice!

Before I expressed my opinion on the performance of the Marathon Supreme, let me tell you that a smaller (20 x 1.6) version of the same tyres are mounted on my folding Dahon Mu P8, and they have been great on that bike.

I must detail the type of riding I do, too. My hybrid bike is used for commuting duties, normally on London roads, and in the hilly part of the Kent countryside; it gets used for all sorts of other duties too: I go shopping and carry full panniers in excess of 20 Kg; I transport my daughter on a rear mounted bicycle seat, inclusive of panniers for day trips to the park; I ride on fire roads and trail tracks. And I expect reliability, handling, durability, and comfort.

Using this particular tyre, I can achieve all of the above objectives.

A large volume tyre allows lower inflation pressures without a great loss of rolling resistance. This comes at a price: rolling weight. But these tyres are not particular heavy even in the larger width, and therefore excel in providing the greater compliance and comfort of lower inflation pressures (40psi) yet resist to punctures and pinch flats, even on potholed roads.

The particular rubber compound used for these tyres is certainly more effective on wet roads than the City Ride tyres I used previously.

The carcass uses a higher TPI construction, which ensures compliance even at higher inflation pressures as required when carrying heavy loads.

The only caveat to be aware of is that these tyres are huge, and effectively increase the overall diameter of the wheel (total circumference 2050 mm): your gears will seem slightly longer as a result; please remember to adjust your cycle-computer accordingly.

Aug 25, 2012

A misdiagnosed loose cassette...

Recently I experienced mis-shifting and chain-jumping on my hybrid commuter bike.

At first I thought it might have been due to a worn out cassette; upon visual inspection, the cassette looked fine.

After a check of my riding records, I realised the chain had done about 1,600 miles and the cassette twice that; but a quick length check on the chain revealed little wear.

I then looked at the rear derailer from the back, and discovered the derailer cage was pointing inward, towards the wheel spokes. I had noticed this a long time before, and back at the time, I replaced the derailer hanger, but that made no difference.

I concluded a worn out derailer was to blame: no indexing attempt seemed to fix the shifting, especially between cogs 4, 5 and 6.

I bought a new chain and a new derailer from Replacing the chain regularly is good practice to ensure reduced wear on cassette and cranks. At 10 GBP for a KMC 8-speed chain with missing-link, it seemed a reasonable expence to face after 6 months riding.

The derailer, upon inspection, seemed to be slightly worn out too, and certainly had seen better days. The new Shimano Acera 8-speed rear derailer looked a worthy replacement for the old Shimano Tourney.

I began removing the old chain and derailer.

Then I removed the rear wheel from the frame to clean the cassette, and that's when I realised the cassette lock nut was not fully tightened and a couple of cogs were loose!

This was the reason behind the inconsistent shifting, and explained why any indexing correction was never lasting longer than a few miles, and why this was getting worse and worse with every passing day.

Unfortunately, I realised this too late. As I had forgotten my cassette tool in the office, I needed to borrow such tool. The guys at Cycles UK in Orpington quickly got it tightened for me for free.

After fitting the new chain and derailer, while I was tensing the gear cable inner wire, the wire snapped from the shifter!

The wire must have rusted near the insertion point and eventually broke off.

Luckily this happened while I was fixing the bike and I had all the tools with me. A second trip to the local Cycles UK shop and 2.99 GBP later, I had a brand new gear inner wire and was able to replace the old one.

This involved opening the 7-speed Shimano shifter and fitting the new wire in place of the old one.

Within minutes I was able to index the new derailer. 

A quick test ride later, I was very happy with the new setup and the new derailer provides crisper changes than the old one ever did even after fitting a new cassette and chain.

So even though the extra expense was not necessary, in the end it was all worth it.

I just wish that I had noticed the loose cassette sooner!

Riding a folding sofa

Today I fitted a very 'comfortable' saddle to my folding Dahon MUP8.
This was upon my wife's request due to my current saddle not being the correct size for her. This was the only other saddle I had available...

During a quick test ride to the high street to fetch some bike parts, it felt like riding a folding sofa!

The ride was way too soft, and the bike felt like wiggling side to side from underneath me. It also made the pedal strokes feel a lot less efficient, bobbing up and down with each power stroke.

The event confirmed to me how much difference a good saddle makes to the riding experience, as much as a good set of tyres makes to the handling.