June 13, 2014

2,200 Mile Update - Grand Bois 'Cerf' 700x28c

Well, where to begin . . . If you read this post back in mid-March, you might remember that I wasn't prepared to make any gigantic claims or "OMG THIS PHONE IS AMAZING!" proclamations; but, my initial impressions had been very positive with regards to Compass Bicycle's 'Grand Bois' tires:  essentially, a great idea realized, and produced for them by the experts at Panaracer in Japan.  The idea?  Well, it's nothing new - that's for certain:  I can remember tire manufacturers claiming their triumph over this goal since the first time I opened Bicycling Magazine many years back:  a tire with the convenience of a clincher and the ride of a tubular!  Pah.  Many a non-believer was born as a result of such bold claims and subsequent let-downs.  Try as they may have, either technology or manufacturing or the need for features which would satisfy the bulk of customers (like flat-protection) would ruin the ride quality, or speed, or handling - or all three.  Back to square one.  It seemed all along that someone not-so-keen on marketing, bottom-line and gimmickry needed to come along and attack this goal; yet, therein lay some trepidation, too - which I'll cover toward the end.

 In essence, it would take many, many pages to adequately describe the physics of what I'm feeling, why it does (or doesn't) work, and what's really happening in that scant cubic inch of rubber, woven poly/cotton and air separating me and my bicycle from the pavement underneath.  I won't
presume to have a better way of describing these things -- as mentioned in the first post, the folks at Bicycle Quarterly have already done that (Google it).  Here, I pledge to keep things sensationalism-free, and - above all - honest.  

The Ride:  one thing I HAVEN'T done and probably should:  I have not swapped my old standard, the Panaracer Pasela TG's (now PT's) back onto the bike to gain a direct, reverse perspective on what I'd initially experienced upon installing the Grand Bois Cerfs.  THAT, likely, would prove quite telling - and as I sit here and pause, I wonder if this report might be premature as a result.  If I decide to do so, I'll definitely post a followup confirmation.  Confirmation... that choice of words alone may be enough, for I'm fairly convinced it will only confirm what my gut tells me.  What I felt over those first few miles had indeed been accurate - so why the heck would I go through the effort of dismounting and remounting (repeat) to confirm it?  Heck, I may not.  I'm confident.  The ride is as good today as it'd been upon initial installation.  In fact - logic (perhaps fuzzy) dictates that the ride may have actually improved since my initial installation, by an interesting process by-which the innertube and tire "seat" together and sorta "marry" to one another... in much the way a tubular is all "one piece", the layers so closely mated the entire assembly acts and moves as "one" entity, a good tube, careful installation, and a healthy dose of talc can emulate this phenomenon - at least a little.  Further, Compass (among other companies like Challenge) profess that the tires themselves will "stretch" a little after a time under pressure.  This is part of the design... some manufacturers dismiss it, others capitalize on it.  If the latter approach is used, the resulting tire is rounder, more compliant, yet, still retains its fortitude.  So, 2,200 miles in - and the comfort still surprises.  I have been on lots of rides since installing these.  Rando folks are fairly tolerant of nasty road surfaces, so this comment really isn't uttered too much during rides - but, I have indeed heard things like "this chip-seal is really rough!" while on a brevet or two.  I had to mentally stop and "feel" for myself, rolling along, and honestly.. I generally ended up with no idea of what they'd been complaining about.  These tires continue to iron out the pavement nicely. 

Handling:  no complaints... I've had occasion to throw the bike into corners that I'd sorta over-cooked, and I've never needed a moment's pause to consider whether or not the tires could handle it.  When I *do* consciously try to feel-out the handling envelope, I've not been disappointed yet.  This is remembering, of course:  I'm not a crit racer, and I ride a rando bike... so, we're not talking about razor's-edge testing here.  Still... I doubt they'd disappoint.  There exists a confidence level here not previously enjoyed with the more "utilitarian" Paselas.

The front tire's tread at 2,200 miles.
Image has had contrast added to 
show detail - note the file tread and
center molding-line.  This is 
typical of any tire in front position,
however - they simply don't receive
the same wear as a rear tire.  This is 
roughly what they would have 
looked like when new.
The rear tire after 2,200 miles.
note the approximate 5-6mm flat
and smooth centerline; and, most
notable, one of the three tread cuts
observed during the test period.
Likely caused by a glancing sharp 
rock, this one contained no left-
over debris, and has remained
tight - an indication of the tread's
makeup and consistency.  Zooming
 in reveals many more tiny
 nicks and evidence of use - but
 I would hardly classify any 
of them as 'cuts.'  When 
considering the treadwear to
date, it's entirely plausible to get
another 2,200 miles out of this one
 in rear position, if I had to guess.
Whether or not I attempt to is 
another question:  at no fault of 
the tire itself, the thinner the 
tread becomes, its ability to
 prevent debris from reaching
 the casing and tube beneath 
will drop dramatically.  Rotating
 now, however, will yield
 a very usable spare.
Treadwear:  while I think this is typical of most tires at any cost, this is perhaps the most telling result for me.  As mentioned in my first impressions test, I had bought-in FULLY expecting there to be a downside to the great ride and such.  After the initial shock of the ride comparison wore off, I started thinking about all the myriad ways these things might disappoint me.  In the past I'd pulled the trigger on "fast" race-day tires for this and that, never really justified, but I think that's also typical of a lot of cyclists like me:  always looking for an edge, when the "edge" I needed really lay within myself... or how many donuts I'd eaten that week... certainly not hiding in my tires.  Each time, once to the tune of $85 a tire, I'd enjoy what I'd perceived to be amazing speed gains, only to be throwing the fully-worn tires away after 750 miles...or continue on only to fix a puncture 'every 50 feet' due to drastically thinned tread.  This is where the Paselas really shone.  With the initial purchase of two new tires, I would then let the rear wear down to about 2,000 miles, then purchase a new front tire, and rotate front-to-back. There remain many opinions across forums and blogs about how "wrong" or "right" I am in my tire rotation approach, yes.  That aside, it has allowed me a satisfying 4,000 miles out of a tire, once it moves from front duty to rear.  I've pushed this as far as 5,000 a tire without much additional consequence.  So, I expected the "gotcha" on the Cerfs to rear it's head here... yet, it hasn't.  With 2,200 miles logged, the original center-line tread file is still clearly visible on the front tire - along with a vague shadow of the center "mold release" line.  The rear tire has squared off a little, perhaps 6mm across, but - that's about it.  For this first run, I am tempted to push the limits.  I carry a spare tire on rides longer than commute-length, so I'm covered - but, my original plan of not reporting back until I saw the rear's casing show through... heck, that's apparently going to take a bit longer than I'd anticipated!  In my estimation, these have worn better and longer than my Paselas normally would.  Compass does indicate they spec'd extra tread for longer wear-life - but, I had honestly read that to mean "these wear faster, so, to compensate we made them thicker."  Okay, so I was wrong again.  No complaints.  As a bonus here, it should be noted that the Paselas have tread siping: water-shedding, or loose surface traction, it might help - but, a clear benefit of the Compass' smoother tread is two-fold:  usually upon tire rotation I find hairline cracking inside the tread siping of the Paselas, as the rubber there is thinner and obviously won't hold up as long as the primary tread.  While this has never caused a problem in use, it has led me to wonder if the tire might be drying out or might invite flats via those cracks, as they also tend to pick up and hold debris of roughly the same size.  The Cerfs, conversely, have a overall smooth tread with a (as shown) light file/cross-hatch tread - which I have come to prefer.  Not only does this prevent the drying/cracking issue mentioned above, it won't invite little rocks and debris from joining your ride the way the Paselas have.
For verification, the permanent marker dating I'd placed on each tire, and its manufacturer label - this, the front tire . . .
. . . and this is the rear.  The tan sidewalls have sustained the usual 'staining' from brake pad silt and road grime, which is a normal result for me, typical of any tan-sidewall tire in my experience.  Adds character!

So, all that handled, where would the 'gotcha' be?


Flats and cuts:  I hesitate to put this in writing, as it will likely become invalid as soon as I mount up for the next ride to work.  First some definitions, so we're clear here.  This is what *I* call this stuff, you may not:  A FLAT is any instance where air inadvertently escapes from the inner-tube by way of a foreign object piercing it, after that object has progressed through the rubber and casing, or sidewall, of the tire surrounding it.  Slow leaks are flats, same as blow-outs or "instant" flats.  A Sidewall cut is fairly self-explanatory.  The sidewalls do not have the same thickness of rubber preventing a foreign object from slicing into the tire's casing; the result looks as if someone had sliced the tire with a knife and is usually 4mm or greater in length - usually resulting in an instant flat or blowout, and creating a difficult repair.  Tread cuts involve ANY visible piercing of the tire's tread which did not (immediately or shortly after) result in a flat.  This includes holes left by foreign objects entering and immediately leaving the tire, or by items which then become embedded - either case would not immediately result in a flat, but may require foreign object removal upon post-ride tire inspection to avoid a future flat.    (Ya'll do perform post-ride tire inspections, right?)  rib rib
The numbers:

Flats:  zero
Tread cuts:  one front, two rear
Sidewall cuts:  zero

Of the tread cuts mentioned, all are less-than 3mm in length, only one is deep enough to show the casing, and only one (rear) contained a remnant of what had created it;  in this case a small piece of sharp brown glass.  Extracted easily.  The important asterisk section:  (another drum-roll)   I don't like having equipment limit my riding... which is really code for "I-don't-have-the-money-to-own-multiple-bikes-for-different-disciplines-and-even-if-I-did-I'd-likely-opt-for-the-one-bike-theory-simply-for-simplicity-and-consistent-fit."  (exhale)

Conditions?  Lots of variables; your mileage WILL VARY.  No two riders or areas are alike -- even in the same neighborhood.  Heck, some would argue no two tires are alike - even among the same brand and model.  If you've had worse, I'm sorry.  I haven't.  Luck?  Maybe?  Who knows.  It is what it is.  Flats are a part of cycling, and shouldn't be feared.  Be prepared, practice fixing them fast.  Simple fact is, whether it was the tires I happen to be reporting upon here, some other random tire, or my old Paselas:  I haven't had any flats recently.
If you're really concerned, you can comment or email for details - but I've outlined my riding conditions and what these tires have seen below as best I can.  I didn't keep an exhaustive log of how many miles on what surface - but what I do have below represents a large hunk of the 2,200 miles, listed top-to-bottom in rough order of how many miles I covered on those conditions:

1) Regular road riding on paved roads, including portions of commutes, weekend rides, fooling around, errands, brevets/permanents on a monthly basis, of at least 200km (occasional 100ks).  Includes a 300 and 400k.  Mostly asphalt overlay, chip-seal, some concrete slab.  Highway shoulders on occasion, mostly in-lane riding.  Visual hazards avoided as best-possible, as with any road rider.  Hazards are typical:  potholes, pavement joints, bridge joints, shoulder gravel, shredded truck tires and associated wires, tree debris, rumble strips, various hardware, wood planks, tacks, staples, nails, nuts and bolts, screws, destroyed shipping pallet debris, roadkill, broken toys, discarded CDs, fast-food trash, plastic junk -- nothing out of the ordinary for any urban/suburban/rural environment.  

2) Consistent commutes to/from work, with rear panniers (weight approx. 15 lbs.) on asphalt-paved trail through wooded areas.  Hazards include downed twigs and tree branches, mostly oaks, maples, elms, hedge.  Acorns, and "squirrel debris", muddy areas near low water crossings, wooden plank bridges, un-even pavement, tree-root upheavals resulting in cracked, jagged, un-even trail surfaces - some older sections worse than others.  Occasional thorn issues, but very light and infrequent.  Lots of standing water, occasional trail flooding and runoff, mud, gravel, sand, and joggers.  So.  Many.  Joggers.

3) Gravel riding, ranging from:  groomed, packed, aged, two & three-row gravel with compressed automobile tire tracks visible.  Loose, newly-spread gravel and white aggregate rock, mostly 1cm-4cm limestone, crushed concrete (recycled) or crushed slag rock - similar to "groomed" gravel mentioned above, but, not mature or traffic-packed.  Rough, minimum-maintenance roads, old gravel, bedrock to packed dirt surfaces, overgrown.  

4) Rail-trail, fine, crushed limestone of various maturity.  Hazards include washouts, downed limbs, branches, mud, rough road crossings.

5) Hard-pack dirt single-track mountain bike trails.  Why not?  Roots, rocks, PBR cans.  (some mine)

6) Some grass riding, but not much.

Approach:  Obviously, I'd been hesitant reporting anything until some time and mileage had passed.  Like that "new pair of shoes" I'd wanted to ensure that the tires faded into the background of importance as I rode.  Also, nothing was off-limits.  Back-roads, truck roads, highway shoulder.  Further, I'm an attentive rider - however, I didn't want that to be confused with being a TIMID rider.  I avoid big stuff, sure, but gravel?  That's not a 'hazard' to me... it's just there; especially if traffic density to my immediate left prevents me from avoiding it.  So, I'd taken to my usual behavior of riding through debris, "ignoring" small junk, hitting pavement joints while seated, etc.  Big obstacles like metal grates, big metal construction plates covering the road were handled reasonably.  I'd also taken railroad tracks at full speed, and more, bunny-hopped obstacles with full loads present, hit curb transitions "wrong", etc.  The end result is what I feel comprises a complete test... my normal style, but also throwing a little caution to the wind to cover those times when it's dark, I miss something, or its hour XX of XXX kilometers, and I just plain miss something or no longer care to steer.  

Environmental concerns:  Temperatures during the period ranged from 40F to 90F, with all levels of humidity and pavement "wetness", which increases the likelihood of any tire picking up and holding onto smaller debris longer compared to a dry surface, thereby increasing the likelihood of it piercing the tread.  This includes riding after/during rain - from sprinkles to all-out thunderstorms and hail, light-to-heavy rain on a recent 200km permanent on questionable pavement - equating to unintended encounters with hazards rendered unseen by heavy rain and runoff.  Temperatures are notable, from a materials perspective:  some rubber compounds benefit from the addition of additives to prevent such issues, however, it is still physically impossible to produce a tire truly "perfect" in "all" conditions - trade-offs, no matter how minute, will exist.  Generally, rubber will become firmer in colder conditions, which may invite easier entry of foreign objects on a loose principle of tread surface rigidity; the same thought which suggests lower tire pressures will help prevent flats; however, I don't feel (chemically) that enough of a temperature range was observed during this test to offer anything conclusive - especially since the flat tally remains at zero.  Off-season considerations:  more testing needed - while I have not personally experienced an increase in a tires tendency to sustain more tread-cuts below X temperature, any such observation - locally - would be offset greatly by an increase in road debris density from off-season road treatments (sand, salt, grit).  Probably not worth mentioning, but it's been widely accepted that the 'dude's keyboard lacks a backspace key.

Other considerations
Weight of rider AND loaded bike, on average = 185-195 lbs.
Bias of weight = most of carried loads are above rear tire
Approach = if I can see a static obstacle (hole, rough joint, RR tracks, similar) I stand on the pedals and try to unload wheels as best possible.  Sometimes it works, sometimes I miss-time it.  Sometimes I miss an obstacle completely and hit it full-force, but this is seldom.  Dynamic obstacles (gravel, debris, roadkill) is avoided as practical - traffic or other conditions will sometimes warrant riding over/thru it, however.
Tire pressure = maintained as best-possible at 80 PSI front, 85 PSI rear.  Atmospherics, temperature changes during course of a ride can vary this by as much as +/- 5%.  Pressure is checked at least every-other ride when access to a floor pump with a gauge is available, and is gut-checked by feel before every ride, sometimes at each control on a long ride to avoid surprises between controls.
Wheels = Mavic Open-Pro (19mm wide), laced standard 3-cross.  (yep, this can affect flat count as well - though negligible)

There you have it.  Is this thorough enough for you, Mr. Needham?

I'll report back once the rear tire's threads are showing, or I wimp out and swap tires early, or if I DO get a ... uhh... should I tempt those odds?  Well, I don't think I need to worry, all things considered.  I already have a third tire in the garage, waiting to be rotated in.  Yes - these tires are no longer a "test" purchase - they have replaced the Paselas as my tire of choice.  How long I wait to rotate it in remains a question... right now, not sure it's necessary. 

 Now, as is the case with ANYthing cycling-related, there is someone out there (I know, because I've read their posts) that has endured a horrifying experience with these exact tires.  I'm not sure what to think about that, other than to mention it reinforces the rule of one's mileage varying, indeed.  Buy with care, ride smart; but, I don't see immediate reason to steer you away from these tires should you choose to try them out.  From my saddle, I'm enjoying the ride.  Simply a terrific tire thus-far, a very comfortable ride, feels plenty fast, and (so far) no big drawbacks observed.  They are everything the folks at Compass professed them to be, and their persistence and hard-work in development definitely shows.  

Now, the trepidation I'd mentioned at the beginning:  while Panasonic is a massive global conglomerate, Panaracer - I have to imagine - is only a small segment of their profits. Further, Compass is a small outfit, contracting out a specialty tire, in what I can only imagine are relatively small batches.  My fear is that someday, for reasons unfair to their quality and following, these tires will no longer be available.  Perhaps the best review I can give them is noting this fear they've inspired.  I only hope that should an end-of-production announcement ever come I have enough notice to perform some quick math and order enough tires to last me the remainder of my cycling life.  To this reviewer and rider, the Cerfs are that good.  Yes, as mentioned in my initial review, this sort of performance comes at a premium - yet, considering the means by-which these came to be and their production numbers, Compass has managed to come to market at prices competitive with or below the cost of many "rando-ish" tires on the market - namely Rivendell's offerings, tires from Challenge, or (at the extreme end) high-grade, hand-made tubulars like Veloflex or FMB.  In that context, they are practically a bargain.

The Grand Bois "Cerf" 700x28c road clincher:  Highly recommended.

Long-term wrap-up report for the first set will come in the future - stay tuned

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