Rims and Tyres

Selecting the best tyre for your Moulton APB depends on many factors, and can have a significant effect on performance. There’s no overall best tyre to suit every rider and their type of use.

Rims

Rim compatibility is the first consideration. The original wide (31mm outside width) Rigida rims fitted to the APB are best used with 1.5 or 1.75in tyres. The Continental Top Touring at 32mm is the narrowest tyre to fit on those rims nevertheless it is a quite marginal fit. The original rims themselves are not especially heavy (425g) but mounting a narrower tyre will mean that it doesn’t get a chance to work properly. A tyre’s casing works most efficiently if the tyre casing is curved out from the rim when inflated. The Rigida AS26 rims fitted to APBs from early 1994 to midway 1997 are narrower (26mm outside width) and compatible with all widths of tyre though the ultra narrow Continental Grand Prixs are a bit marginal. These Rigida rims are strong, reliable and quite light (365g) in weight though a little agricultural in appearance. The same width Alesa 4019 which replaces the Rigida AS26 on APBs is a lot prettier and a bit stronger due to small box sections in the corners but weight has gone up a little to 390g. They are pretty much bombproof but like the Rigidas pretty marginal with Grand Prix tyres. For the Grand Prix tyres the best rims are undoubtedly the narrow Sun. The CR16 photographed are narrower than the Rigida and Alesa. They are no longer available but are replaced by the M13 which is a little bit narrower still at just under 20mm. They are available in 28, 32 and 36 hole drillings and are a proper eyeletted, box section rim. They are compatible with all tyres up to 1.5in in width. Sun rims are imported by Evolution Imports, Tel 0181 290 0807. 20in rims have to be ordered specially – delivery takes about three to four weeks.

Tyre Design

Tread pattern has very little effect on a performance of a tyre on the road. The semi-slick City Jets are great performers in the wet or dry. Tread compound is more important. Off-road, tread pattern is important grip wise. Off-road tyres with their chunky treads inevitably have a higher rolling resistance on the road than their more lightly treaded cousins in part due to all the little knobbly bits flexing. Nokian have turned the science of tyre casing design on its head with their low rolling resistance tyres with coarsely threaded two-ply casings. Conventional wisdom has it that finely threaded tyre casings are more supple and offer lower rolling resistance. In tests the multiple ply, finely threaded casings are quite puncture proof but don’t roll as easily. They are however very tough. Weight affects the feel of a tyre. Heavier tyres feel more sluggish though may roll easily. There’s no doubt that a truly light tyre makes for a really lively feel due to the ease with which it can be accelerated. Tyre wear is difficult to compare except when tyres are ridden by the same rider in similar conditions. Heavier riders with heavier touring loads on hot, dry roads will wear tyres far faster than lighter riders without a load in cooler conditions. The wear reported on here is as comparable as it can be. I’d be very pleased to hear of long term reports on tyre wear and performance from Moultoneers.

Tubes

With the narrower tyres I feel the best tube to use is the Michelin 18 x 1 3/8in. These Michelin tubes are light and reliable. These normally come fitted with a Woods valve that can be unscrewed and replaced with a Presta valve if you can find some spares from older style Presta valve tubes. Presta valves are easier to inflate to high pressures with a hand pump than Schraeder. For long distance touring Schraeder valves have the advantage that they can be pumped up anywhere. If using an airline extreme caution is advised as it’s very easy to blow the tyre off the rim. Continental offer tubes with Presta valves to fit both the Top Touring and Grand Prix. The Grand Prix fitting tubes fit the City Jets nicely as well. The Top Touring tubes fit most tyres in the 1.35 to 1.5in widths.

Continental Grand Prix

Max rec. pressure: 120psi
Width when inflated: 26mm
Weight: 206g 

Ultra narrow tyre that only really works well on the narrow Sun rim. Marginal on 26mm Alesa and Rigida rims. Quite tough with anti-chafing strip, but not very long lasting. Expect about 1000 miles or a bit more if light or unladen. Ultra light weight gives very lively feel but tested rolling resistance places it only a little better than City Jet or City Runner.

Continental Top Touring 2000

Max rec. pressure: 70psi
Width when inflated: 32mm
Weight: 408g

Tough touring tyre with anti-chafing strip and directional road tread. Tread direction depends according to Continental on whether used on front or rear wheel. No rolling resistance figures but subjective feel is that it is a little sluggish. No experience of lasting qualities as yet. Lowish recommended maximum pressure can be comfortably exceeded. Breaker ply in tread should ensure good puncture resistance.

Michelin Service Course

Max rec. pressure: 50psi
Width when inflated: 38mm
Weight: 283g 

Not available to buy. Experimental tyre produced for Shell Marathon vehicle competitions. Ultra low tested rolling resistance similar to the very best tubular or wired-on 700C tyres even at low pressures. Despite modest recommended maximum pressure is capable of far more. Folding Kevlar bead contributes to light weight. Very thin, pliable slick tread and carcass – tread cuts too easily for normal road use.

Nokia Mount and City 20 x 1.75/2in

Max rec. pressure: 50psi
Width when inflated: 41mm
Weight: 556g

No longer available though some shops may have stocks. Quite heavy – it doesn’t feel as lively as the lighter Continental, Primo or Schwalbe tyres. Despite agricultural appearance rolls as well as any of the commercially available tyres when pumped to 80psi. Long lasting and tough though occasionally problems with carcass bulges or tread twisting. Modern replacement is Pacer S.

Nokia Mount and Ground 20 x 1.75/2in

Max rec. pressure: 45psi
Width when inflated: 42mm
Weight: 595g 

No longer commercially available. Fitted as standard equipment on Land-Rover APBs until arrival of X-Trak. At its maximum recommended pressure of 45psi rolling resistance is high but can be pumped for road use to 80psi where rolling resistance is less. Prone to the same occasional carcass ailments as Mount and City. Good chunky tread for off-road use which clears mud well.

Nokia Pacer S 20 x 1.75in

Max rec. pressure: 65psi
Width when inflated: 41mm
Weight: 565g 

Modern replacement for Mount and City. More open, far more modern looking tread on what must the same tyre carcass. No rolling resistance figures but probably very similar to Mount and City, very good. Similar heavy weight though makes for a bit of a dead feel compared to lighter tyres. Available like most Nokian tyres with cream or black side walls.

Nokian City Runner 20 x 1.5in

Max rec. pressure: 72psi
Width when inflated: 37mm
Weight: 435g 

A narrower and much lighter 20in tyre from Nokia. Fitted as standard to APB S7 and APB3s. Has much livelier feel than the wider Nokians but rolling resistance figures are not quite as good as Mount and City but better than Schwalbe City Marathon and at least as good as Monte Carlos. Tread life is good like all the Nokians.

Nokian X-Trak

Max rec. pressure: 65psi
Width when inflated: 41mm
Weight: 568g 

New replacement for the much liked Mount and Ground. Directional off-road tread Nokian make specific recommendations according to conditions and to front or rear wheel. Modern tread pattern is as good as it gets in mud though could be a little deeper to further improve mud clearing abilities. No rolling resistance figures but probably similar to Mount and Ground. Similar weight to Pacer S.

Primo Comet 20 x 1.35in

Max rec. pressure: 100psi
Width when inflated: 32mm
Weight: 275g 

A light, skin walled tyre with beautiful herringbone tread pattern. Supple, thin casing subjectively makes for an easy rolling tyre. Light weight contributes to a very lively feel. Experience of 16 x 1 3/8in tyre on Bromptons and original Moultons suggests tyre to be reliable and have a long life. One of the best tyres available at present, an excellent compromise.

Schwalbe City Jet

Max rec. pressure: 100psi
Width when inflated: 29mm
Weight: 263g 

Discontinued though still available from Phoenix Cycles. An old favourite and still one of the best. Good rolling resistance that definitely improves with use. Very tough and puncture resistant tyre that wears well over high mileages. Tread will cut but no further damage normally results. Like the Primo an excellent compromise. Good wet weather grip. Lighter than anything except Grand Prix.

Schwalbe City Marathon 20 x 1.25in

£14.65
Max rec. pressure: 115psi
Width when inflated: 28mm
Weight: 315g 

The replacement for the City Jet. Schwalbe have added a puncture resistant Kevlar belt under the tread – this has increased the weight by about 40g. The tread pattern and more importantly shape has changed; rolling resistance tests show it to now be a relatively poor performer. But it is tough and lasts well, 3000 miles is quite possible as a rear tyre.

Vredestein Monte Carlo

Max rec. pressure: 90psi
Width when inflated: 34mm
Weight: 368g 

One of the first good tyres widely available. It features an additional PRS layer to reduce punctures – this seems to work well. Rolling resistance on our well worn sample was good; it would probably not perform as well when new and would push it further down the rolling resistance table a little. Wears better than Grand Prix but not as well as the Schwalbes.

Verdict

Very much a horses for courses decision. The Nokian X-Trak (about £9) is the tyre if you want to explore off-road. Another possible option is the Ritchey Megabite which is available in 20 x 1.75in size from some BMX specialists. For mixed use – commuting, day touring and the occasional loaded tour the choice narrows down to the City Jet (£19 from Phoenix Cycles) and the Primo Comet about £17. Both are really lively light tyres which are not too fragile. The Nokian City Runner is an economically priced alternative at £9. For heavy weight touring and light off-road use the Continental Top Touring (about £18), Vredestein Monte Carlo (about £15) and Schwalbe City Marathon (about £15) are all contenders. The Schwalbe is longer lasting than the Monte Carlo but we don’t have enough experience with the Top Touring to compare it and the Schwalbe. The Nokians are all easy rolling economically priced tyres (about £9) which represent outstanding value for money. Despite rolling easily they don’t feel very lively due to their weight. For those still on the wide rims these are the best tyres though Primo offer their lightly treaded V-monster tyre from BMX specialists which should be an excellent performer as well. The Continental Grand Prix (about £20) feels very lively, rolls quite easily but only performs at its best when mounted on the narrowest rims.


Some additional observations

Discussion on the subject of 20″ (406) tyres regularly crops up un the Moulton mailing list and on the Bike Friday Yak list. Generally the exerience of riders agrees with the views expressed by Hilary Stone in the above masterclass article.

The Schwalbe City Jet has remained available rather longer than inplied in Hilary’s article, but supplies do now seem to be coming to an end. Its demise is to be regretted, since experience of users is that it offered a particularly good combination of low rolling resistance, good life, reasonable puncture resistance and grip. For general road use most riders comment very favourably on the Primo Comet, and that now seems the best tyre overall to choose. Despite the relative lack of tread, in most circumstances it gives good life and puncture resistance as well as a reasonable grip in addition to low rolling resistance. However, off-road or in wet conditions some care should be taken due to the minimal nature of the tread. The Continental Grand Prix remains favoured by those seeking the ultimate in terms of performance (rolling resistance), though the benefits over the Primo in this respect are small, and in other respects the Primo seems to have the edge. The Continental Top Touring is a rather more robust and slightly more treaded tyre for those who want this, and are prepared to put up with higher rolling resistance. Serious off-road performance rarely gets discussed in the mailing lists, so ther is nothing to add to Hilary’s comments at present on this subject.

The Ferret
3 January 1999


REMEMBER THE WARNING

Modification, repair and renovation work should only be carried out by qualified people. If you do not have the experience and/or expertise to judge whether any procedures described in Masterclasses are correct, DO NOT ATTEMPT TO DO THE JOB. The information given in Masterclass articles is intended to act as a reminder to capable people who are carrying out repair work. The authors, the Moulton Bicycle Club and its Officers accept no responsibility for work carried out by owners or their agents, whether that work is done in accordance with any information contained in these articles or not.