At road.cc every product is thoroughly tested for as long as it takes to get a proper insight into how well it works. Our reviewers are experienced cyclists that we trust to be objective. While we strive to ensure that opinions expressed are backed up by facts, reviews are by their nature an informed opinion, not a definitive verdict. We don't intentionally try to break anything (except locks) but we do try to look for weak points in any design. The overall score is not just an average of the other scores: it reflects both a product's function and value – with value determined by how a product compares with items of similar spec, quality, and price.
Good scores are more common than bad, because fortunately good products are more common than bad.
With an internally-cabled carbon frame, electronic shifting and hydraulic disc brakes De Rosa's Idol is pretty much the definition of today's road bike technology. It's a lovely bike to ride and dare I say it pretty to look at (sorry 'discs on road bikes' haters) but with an 8.5kg weight and an average wheelset for the price tag I can't help but feel it's a bike looking for a marketplace.
De Rosa reintroduced the Idol to their range for 2014 though rather than bring it back in its original guise they've embraced everything that's new in the cycling world. The line-up includes both rim and disc brakes with a range of kit at different price points. Our test model is the Ultegra Di2, Shimano BR-R785 hydraulic disc equipped option priced at £3699.
On paper the geometry places the Idol somewhere between a race bike and an endurance style machine. You've got 73° angles for the seat and head tubes to give quick handling and a forward race position but the near meter long wheelbase calms things down a bit.
This translates to the road as well. The feedback is of a solid, planted bike and you always know what it's up to and going to do. Rough surfaces do little to faze it and the Idol is a very mild mannered machine making it a decent choice for long days in the saddle.
The 54.5cm size we've got in on test actually has a 56cm top tube length and 15.4cm head tube. The 54.5 comes from the seat tube which De Rosa measure from BB to just above the top of top tube. Although the tube is curved I wouldn't go as far as to say that the Idol is a compact. For its size it has quite a long cockpit, again hinting at the performance riding it's intended for.
This allows you to adopt a flat back position in the drops for those efforts off the front or into a headwind. Spreading your weight across the bike makes for balanced descending and thanks to the tapered head tube and steerer the front end remains tight when you're pushing into the bends. The handling is quick enough to get you in and out of trouble and the Idol is fun to ride but it's not a challenge either.
This pretty much sums up the entire ride feel of the Idol. It's subdued, a bit lacking really. Accelerate it from cruising pace and yeah you get the speed increase but you don't really get anything back for your effort, it doesn't excite in a way a frame of this style should.
Climbing is hampered by the Shimano RX31 wheels. At 1831g, they're pretty heavy for the wheels on a bike that costs the thick end of four grand. We reviewed these at the end of last year and my opinion mirrors Dave's in that they are very good wheels but they aren't something you want on a lightweight speed machine.
It's a shame as they just take the fun level down a notch and don't let the Idol really show its full capabilities when attacking hills or accelerating.
I swapped in a set of lighter weight wheels from another test bike and the 300g drop in rolling weight did make a marked improvement to climbing and acceleration but it further highlighted the lack of excitement in the frame regardless of speed.
This is my first long term test on Shimano's new BR-R785 hydraulics and they are literally amazing to use. There is a lot of talk about modulation when it comes to discs and this is the real bonus with the Shimano brakes; you can feel everything at the lever. The rear wheel does lock, only about the same as a pin sharp caliper brake but you can just feed out the power a tiny bit and it's instant. Not only is braking better in the wet it's more controllable too.
I was sceptical of Shimano's recommendation of 140mm rotors front and rear as previous cable or hydraulic/cable brakes I've ridden with 140mm rotors have lacked the power for heavy braking. I've much preferred the feel of 160mm discs.
With the BR-R785's it'd be overkill and after some hard braking efforts from 50+ mph there haven't been any symptoms of fade or boiling fluid.
The new hydraulic levers aren't group-specific but these Di2 options fit the hand well even with the hydraulic reservoir sitting at the top. In fact electronic shifting seems to work really well with hydraulic discs, you can modulate the braking while changing gear at the same time which is really noticeable on the twisty sections and allows you to set the bike up for the corner easier.
Di2 continues to get better and better in its operation and this latest Ultegra iteration has a much lighter feeling touch to the buttons and a smoother shift even under load. The rear mech barely looks any different from the mechanical version now which is better for aesthetics and the front is getting there.
It's a full Ultegra groupset which is what you'd expect for a bike of this price. The four arm chainset paired with that massive BB junction means stiffness under acceleration is phenomenal.
As always once set up it stays spot on. The Idol uses the latest internal version which means that once everything is installed you don't need to touch it again. When it comes to charging the battery everything is taken care of at the junction box under the stem, you just plug the USB cable in there.
The 50/34T chainset paired with an 11/25T cassette gives you a decent spread of gears though to make the ascents a touch easier on the knees.
The Idol Disc uses an upgraded frameset over the standard rim braked version to cope with the extra braking forces put through it from the discs.
It's a blend of T1000 (70%) and T800 (30%) Super High-Modulus carbon fibre with a lot of emphasis around the chainstays and fork legs. Using these materials and lay up De Rosa say that they've created a stiff frame that is also comfortable out on the road.
The frame shape is a common theme that we see on this style of bike. Starting with a tapered headset you get a large diameter (well it's more of a triangular profile but you get the gist) oversized downtube for tight steering and a stiff front end.
The bottom bracket uses the Pressfit BB386 standard with its size dictating the huge BB junction which practically matches the 34-tooth chainring in diameter. It certainly gets the power down in conjunction with the oversized box section chainstays. These remain narrow before kicking out at near the dropouts for extra heel clearance due to the 135mm disc hub spacing.
The upper half of the frame, top tube, seat tube and seatstays all take on a much more swooping, slender approach to absorb as much road buzz as possible from the frame, promoting much more comfort in real terms than any lay up or material choice.
The disc fork doesn't suffer from any braking force issues at all and it's very stiff in all directions. The tapered 1 1/8in to 1 1/2in diameter steerer is carbon, keeping the weight down. You get internal disc hose routing which keeps things tidy and the dropouts are for a standard 9mm quick release, as are the rear dropouts.
All the cabling on the frame is internal too using blanking plates and differing inserts depending on whether you are running electrical or mechanical shifting. It gives a tidy look to the frame and the entries on the left hand side of the down tube are staggered to avoid tight angles.
The handlebars and stem are both 3T's Ergosum Pro, mid-range alloy components that marry good looks with stiffness and plenty of position options. It's a stiff set up but not over the top and works well with the frame.
The seatpost is from FSA. It would have been nice to see a 3T one to complete theme but the carbon SLK fitted does the job and is easy to adjust. I've used loads of FSA posts over the years and they always remain durable.
On top of this is a Prologo Keppa ti 2.0 saddle. Harsh would be a polite word for it I reckon. It's not uncomfortable but it's borderline. Should you be putting the miles in it would pay to invest in some decent shorts.
As I mentioned earlier the Shimano RX31 wheels are heavyweights for a bike of this cost and class. Acceleration and climbing are both blunted but on the plus side they are pretty much bombproof. These have remained true throughout the test period, they've seen some rain and salt too without any ill effects to the hub or bearings.
The Continental Grand Sport tyres roll pretty well in this 25mm guise but again could do with upgrading to make the most of the frame. Grip is good though and they've resisted punctures and cuts. You can squeeze 28mm tyres into the frame but it's tight and doesn't leave much room for foreign objects.
The De Rosa Idol is a nice bike. The frame looks good with all the swoopy profiles and it certainly delivers on the stiffness front while being relatively comfortable. It handles well too, nothing special but it holds a line and you get plenty of feedback through your contact points.
The frameset is £2399.99 on its own which is a massive chunk of money so it's easy to see why the budget wheels have been specced and this leads me to my biggest issue with the Idol Disc.
What is it trying to be? You can't race it, not yet anyway, because of the discs but even if you could it's way too heavy in this guise. You could spend more on lightweight wheels but then you're looking at least at a £4k build price for a bike that will struggle to compete with something half its price.
Sportive riding? Yeah okay you don't need the acceleration but the added weight of those wheels comes into play again: sportives tend to be hilly.
It's like De Rosa have taken a standard rim-braked Idol and added discs just because everyone else has. That's increased the weight and price while giving you lower spec heavy wheels but the ride and handling just doesn't have the sparkle, the wow factor that I expect from a bike at this price to justify the outlay.
Good but doesn't quite hit the mark especially at this price
If you're thinking of buying this product using a cashback deal why not use the road.cc Top Cashback page and get some top cashback while helping to support your favourite independent cycling website
Make and model: De Rosa Idol Disc
Size tested: 54
State the frame and fork material and method of construction. List the components used to build up the bike.
Frame: Super Hi-modulus carbon, disc specific
Fork: Super Hi-modulus carbon, disc specific
Steerer: Tapered 1 1/8 - 1 1/4
Wheelset: Shimano RX31
Brake Levers/Gear Shifters: Shimano Hydraulic Di2
Front Derailleur: Shimano Ultegra Di2
Rear Derailleur: Shimano Ultegra Di2
Brake Calipers: Shimano BR-R785 Hydraulic Discs
Chainset: Shimano Ultegra with Token Pressfit BB
Chain: Shimano Ultegra 11 speed
Cassette: Shimano Ultegra 11 speed (11x25)
Handlebars: 3T Ergosum Pro
Stem: 3T Ergosum Pro
Seat Post: FSA SLK
Saddle: Prologo Keppa ti 2.0
Tyres: Continental Grand Sport
Tell us what the bike is for, and who it's aimed at. What do the manufacturers say about it? How does that compare to your own feelings about the bike?
Looking at the geometry charts the Idol is a fast endurance style frame with sporting aspirations but with an extended wheelbase and head tube to give a stable, slightly more upright ride. It delivers on the stability but is found lacking on the 'sporting'.
Tell us about the build quality and finish of the frame and fork?
The overall quality looks good although the naked raw carbon finish isn't to everyone's taste. The clean look of the internal cabling makes for a stylish uncluttered looking frame.
Tell us about the materials used in the frame and fork?
A mix of T800 and T1000 high modulus carbon used in various layups and orientations to provide the ride quality, stiffness and resistance to those disc braking forces.
Tell us about the geometry of the frame and fork?
For a 54cm frame it has a long top tube of 56cm which does lead to quite a stretched out position. Steep angles give tight handling.
How was the bike in terms of height and reach? How did it compare to other bikes of the same stated size?
Height is pretty standard although the reach is a bit of a stretch, geo charts are here: www.derosanews.com/english/DEROSA30_Idol_Grey_Disk.html
Was the bike comfortable to ride? Tell us how you felt about the ride quality.
For such a stiff frame the Idol is comfortable, not what you'd call an armchair ride but fine for a few hours in the saddle.
Did the bike feel stiff in the right places? Did any part of the bike feel too stiff or too flexible?
Stiffness at the key points, head tube, fork and BB area all show little in the way of flex.
How did the bike transfer power? Did it feel efficient?
Power transfer was good through the frame. The wheels take the edge of though
Was there any toe-clip overlap with the front wheel? If so, was it a problem?
Yes, a small amount.
How would you describe the steering? Was it lively, neutral or unresponsive? Neutral, missing a bit of sparkle.
Tell us some more about the handling. How did the bike feel overall? Did it do particular things well or badly?
The handling is fine, very easy to live with and you get decent levels of feedback. The whole ride just feels a little muted though.
Which components had the most effect (good or bad) on the bike's comfort? would you recommend any changes?
The saddle is quite harsh so I would change that to something a little more plush.
Which components had the most effect (good or bad) on the bike's stiffness? would you recommend any changes?
The alloy 3T bars and stem are very stiff without being uncomfortable.
Which components had the most effect (good or bad) on the bike's efficiency? would you recommend any changes?
Change the wheels for something lighter to give the Idol a bit of a boost.
Tell us some more about the drivetrain. Anything you particularly did or didn't like? Any components which didn't work well together?
Ultegra Di2 is a beautiful groupset that is ever improving. The levers work so well with the hydraulic setup with regards to hand position and Shimano's 11 speed cassettes give a great range of gears.
Tell us some more about the wheels and tyres.Did they work well in the conditions you encountered? Would you change the wheels or tyres? If so, what for?
Good wheels and tyres but so under-specced for a bike of this price.
Tell us some more about the controls. Any particularly good or bad components? How would the controls work for larger or smaller riders?
3T stuff is decent quality and looks good too. The bars were comfortable with their shallow drop working for riders with smaller hands.
Did you enjoy riding the bike? I could take it or leave it.
Would you consider buying the bike? No.
Would you recommend the bike to a friend? No.
Anything further to say about the bike in conclusion?
The Idol just feels like it's lacking something to me, there is no real excitement. It doesn't do anything badly, it's a competent bike but at this price it's found wanting in almost every aspect.
Age: 36 Height: 180cm Weight: 76kg
I usually ride: Kinesis T2 My best bike is: Kinesis Aithien
I've been riding for: 10-20 years I ride: Every day I would class myself as: Expert
I regularly do the following types of riding: time trialling, commuting, club rides, sportives, fixed/singlespeed,
With 20 years of road cycling and over 150,000 miles in his legs it's safe to say Stu is happiest when on the bike whatever the weather. Since writing his first review for road.cc back in 2009 he has also had a career in engineering including 3D-CAD design and product development, so has a real passion for all of the latest technology coming through in the industry but is also a sucker for a classic steel frame, skinny tyres, rim brakes and a damn good paintjob.
His fascination with gravel bikes is getting out of control too!