Toyo OBSERVE GSI 6 HP vs Petlas Glacier W661
Ahead in each discipline
The Toyo OBSERVE GSI 6 HP and the Petlas Glacier W661 have met in 1 independent tests and the record is level at 0-0. The OBSERVE GSI 6 HP was stronger in snow and ice, the Glacier W661 in dry and wet.
Performance profile
14 measurements from the one shared test, each tyre shown as its share of the better figure.
Where each is furthest ahead
OBSERVE GSI 6 HP
Glacier W661
Point at or tap any spoke for both tyres' figures.
In each test the better of the two figures counts as 100% and the other as its share of it, so a 36 m stop against 34.2 m is 95%; each spoke averages the shared tests that recorded it.
Where each scores higher
OBSERVE GSI 6 HP
Glacier W661
Point at or tap any spoke for both tyres' figures.
Category scores are percentiles among tyres of the same season and class: 90 means this tyre out-performs 90% of them, measured across every test we hold, not only the ones it appeared in.
Every measurement, side by side
Both tyres' figures from the one test that ran them together, on the same car, in the same size, on the same day. The bar grows towards the tyre that did better.
| Measurement | OBSERVE GSI 6 HP | Gap | Glacier W661 |
|---|---|---|---|
| Dry Glacier W661 ahead | |||
| Dry Braking m | 29.8 | 2.7% | 29 |
| Subj. Dry Handling pts | 8 | 25% | 10 |
| Wet Glacier W661 ahead | |||
| Wet Braking m | 36.6 | 18.9% | 29.7 |
| Wet Handling s | 34.8 | 3.2% | 33.7 |
| Subj. Wet Handling pts | 7 | 28.6% | 9 |
| Snow OBSERVE GSI 6 HP ahead | |||
| Snow Braking m | 50.9 | 4.3% | 53.2 |
| Snow Traction s | 6.2 | = | 6.2 |
| Snow Handling s | 49.3 | 3.1% | 50.9 |
| Subj. Snow Handling pts | 7 | 16.7% | 6 |
| Ice OBSERVE GSI 6 HP ahead | |||
| Ice Braking m | 48.1 | 4.8% | 50.5 |
| Ice Traction s | 6.5 | 1.5% | 6.6 |
| Ice Handling s | 67.3 | 4.9% | 70.8 |
| Subj. Ice Handling pts | 5 | 25% | 4 |
| Comfort Level | |||
| Subj. Noise pts | 8 | = | 8 |
Braking distances and lap times are better when lower; speeds, wear and grip figures when higher. A test's figures are its own: sizes, cars, surfaces and temperatures differ from one to the next, which is why the averages here are only ever of tests the two tyres shared.
Head to head in 1 test in 2020
Each row is one published test in which both tyres ran on the same car, in the same size, on the same day. The line is the whole field, winner on the left.
| Test | OBSERVE GSI 6 HP | Field | Glacier W661 |
|---|---|---|---|
| 2020 Nordic and Studded Winter Tyre Test | P10 of 12 | P10 of 12 |
OBSERVE GSI 6 HP vs Glacier W661: your questions
Is the Toyo OBSERVE GSI 6 HP or the Petlas Glacier W661 the better tyre?
The Toyo OBSERVE GSI 6 HP and the Petlas Glacier W661 have met in 1 independent tests and the record is level at 0-0. On the Tyre Reviews Score, which weighs every test and review we hold, the OBSERVE GSI 6 HP scores 5.3 and the Glacier W661 5.2 out of 10.
Which is better in the wet, the OBSERVE GSI 6 HP or the Glacier W661?
The Glacier W661 led 3 of the 3 wet measurements the shared tests recorded.
Which is better in the dry?
The Glacier W661 led 2 of the 2 dry measurements the shared tests recorded.
Which is better in snow?
The OBSERVE GSI 6 HP led 3 of the 4 snow measurements the shared tests recorded.
Which is quieter and more comfortable?
Owners rate comfort 8.5/10 for the OBSERVE GSI 6 HP and 5/10 for the Glacier W661.
What do owners say?
Owners rate the OBSERVE GSI 6 HP 84% from 14 reviews and the Glacier W661 57% from 1.
Are they available in the same sizes?
The OBSERVE GSI 6 HP is made in 39 sizes (16 to 21 inch) and the Glacier W661 in 17 (13 to 17 inch). 8 sizes are available in both. On the EU label the OBSERVE GSI 6 HP is graded E for wet grip and E for rolling resistance in most sizes; the Glacier W661 C and C.
More comparisons with these tyres
Run either of these?
Your review is the part of this page no test can supply: how the tyre wore, how it aged, what it was like in the rain in year three. It takes about five minutes.
Where this data comes from
Finishing positions and measurements are transcribed from each published test. A test only counts here when both tyres ran in it, so every figure was recorded on the same car, size and day as the one it is compared to.
About the TR Score
The Tyre Reviews Score rates each tyre out of 10 from every independent test result and vetted owner review we hold, so two tyres can be compared even before a test has run them together.
Who does the testing
Every test published as a Tyre Reviews test is run by Jonathan Benson, who has been testing tyres independently since 2007.